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User Guide to the Centenary Edition of the GEBCO Digital Atlas

1. User Guide to the Centenary Edition of the GEBCO Digital Atlas and its data sets Editor Meirion T Jones Chairman GEBCO Sub Committee on Digital Bathymetry GDA Manager Pauline Weatherall BODC GDA Software Raymond N Cramer BODC April 2003 Natural Environment Research Council Page of 141 Preface by the Chairman of GEBCO It gives me great pleasure to introduce to you the Centenary Edition of the GEBCO Digital Atlas which presents the most complete and up to date Atlas of the bathymetry of the world s ocean floor The Centenary GDA is a substantial revision of the earlier issues of the GDA in 1994 and 1997 including a major extension of the bathymetric interpretation of the Indian Ocean and the adjacent parts of the south east Atlantic and the south western Pacific the work of the indefatigable Dr Robert L Fisher The bathymetry of the entire Arctic Ocean has been revised by Dr Martin Jakobsson Mr Norman Cherkis and others and includes numerous sounding data released by the USA and Russia Parts of the north and equatorial Atlantic the south west Pacific and the Southern Ocean have been revised Regrettably a revision of large parts of the Pacific Ocean have not yet been undertaken Where it has been possible the products of the International Bathymetric Chart projects of the IOC have been incorporated into the GDA There are still huge areas of the oceans in which no sounding data have been acquired In
2. In 1965 an agreement was reached between the IHB and the French Institut G ographique National IGN for the production of the GEBCO Fourth Edition Responsibility for the cartographic compilation publication and sales of GEBCO was taken over by IGN with IHB acting as the co ordinator for the whole activity The volunteering Hydrographic Offices supplied IGN with updated copies of their 1 1 million collected soundings sheets for use in compiling the GEBCO sheets The IGN was responsible for drawing the contours and selecting the soundings with the French Hydrographic Office verifying this work The project was overseen by the GEBCO Committee a consultative body with membership drawn from national Hydrographic Offices the Scientific Committee on Oceanic Research SCOR and Page 27 of 141 the International Association for the Physical Sciences of the Oceans IAPSO An Editorial Board of the Committee was responsible for the verification and correction of geomorphological details With the new arrangements 7 GEBCO sheets 4 of the Fourth Edition and 3 of the Third Edition were published between 1966 and 1973 However under this system there were a number of drawbacks principally the lack of scientific input in the compilation of the various sheets These inadequacies were highlighted by the SCOR Working Group on Morphological Mapping of the Ocean Floor Even to the present day the sounding coverage of the world s oceans is very patch
3. 1980 Mar Geol 35 243 275 and Rona P A Schneider E D and Heezen B C 1967 Deep Sea Res 14 625 633 48 Shipley T H 1975 Ph D Thesis Rice Univ Houston Texas 156 pp Also Taylor P T Stanley D J Simkin T and Jahn W 1975 Mar Geol 19 139 157 Page 121 of 141 49 Tucholke B E and Ewing J I 1974 Geol Soc of Amer Bull 85 1789 1802 50 Flanagan J P Gilg J G Jones C R Marchant F L Murchison R R Rebmon J H Snodgrass L W Sorenson F H and Whitney J C 1981 Caribbean Bathymetry USGS Open File Map 51 Sorenson F H Snodgrass L W Rebmon J H Murchison R R Jones C R and Martin R G 1975 USGS Open File Map 75 140 52 Canadian Hydrographic Service 1970 1980 Natural Resources Maps 1 250 000 MATERIAL CONSULTED OR INCLUDED WITH MAJOR MODIFICATIONS Bosshard E and Macfarlane D J 1970 J Geophys Res 75 4901 4918 Closs H Dietrich G Hempel G Schott W and Seibold E 1969 Reisebericht bearbeitet Meteor Forschungsergebnisse Reihe A 5 83 pp Embley R W and Jacobi R D 1977 Mar Geotechnology 2 Mar Slope Stability Crane Russak and Co 205 227 Gorini M A 1977 Ph D Thesis Columbia University Grant A C 1979 Tectonophysics 59 71 81 Kumar N and Embley R 1977 Geol Soc Amer Bull 88 683 694 McGregor B A Betzer P R and Krause D C 1973 Mar Geol 14 179 190 Pasenay H 1973 Schiriften des
4. ANNEX L 16 GEBCO Sheet 5 16 MAJOR UPDATE NOTE Much of the bathymetry in the area of GEBCO sheet 5 16 has been replaced by the revised bathymetry contained in GEBCO sheets G 07 Weddell Sea and G 08 All that remains from the original sheet are the following areas a 66 72 S 66 78 W d 56 60 S 20 78 W b 60 66 S 75 78 W e 50 56 S 12 78 W and c 60 64 5 S 12 15 W f 46 40 50 S 70 78 W GEBCO Sheet 5 16 was published in June 1981 by the Canadian Hydrographic Service under the authority of the IHO and IOC Scientific Coordinators Cartography by Published Chart Projection Mercator Scale Ellipsoid Southern Limit Western Limit Northern Limit Eastern Limit Digitized by Geographic Area Digitized Contour Units Contours Present John La Brecque Philip D Rabinowitz and Carl Brenner Lamont Doherty Geological Observatory New York U S A Geoscience Mapping Unit Canadian Hydrographic Service GEBCO SHEET 5 16 June 1981 1 to 10 million at the Equator International 1924 Hayford 72 00 S 078 00 W 45 00 S 020 00 E 40 S for east of 5 W Bureau Gravimetrique International Toulouse France in collaboration with Institut Geographique National Paris France and the British Oceanographic Data Centre as for published chart except for the area north of a line joining the points 78 W 46 40 S 70 W 46 40 S 70 W 50 S 20 E 50 S
5. Scientific Coordinators Cartography by Published Chart Projection Mercator Scale Ellipsoid Southern Limit Western Limit Northern Limit Eastern Limit Note Digitized by Geographic Area Digitized Contour Units Contours Present Jacqueline Mammerickx and Stuart M Smith Geological Research Division Scripps Institution of Oceanography La Jolla USA Geoscience Mapping Unit Canadian Hydrographic Service GEBCO SHEET 5 07 March 1982 1 to 10 million at the Equator International 1924 Hayford 00 00 N 180 00 W 46 40 N 077 00 W The area from 77 to 90 W is only covered south of a line joining the points 15 N 90 W and 8 16 N 77 W NERC Unit for Thematic Information Systems Reading UK in collaboration with the British Oceanographic Data Centre as for published chart except for the area north of Central America i e the area north of a line joining the points 16 N 90 W 8 16 N 82 W 9 15 N 79 W The digital data for this area is covered in GEBCO sheet 5 08 The digital bathymetric contour data for the western part of the Gulf of Mexico the area 90 to 98 W 18 to 30 N is also omitted This area is covered in the digital data for GEBCO sheet G 03 bathymetric depth in corrected metres 0 200m 500m and at 500m intervals thereafter down to 7000m However for many areas intermediate contours are also included and the digital data set will be found to include addit
6. Vanney J R and Johnson G L 1976c The floor of the Ross Sea and adjacent oceanic provinces US Antarctic J 11 4 231 233 Vanney J R and Johnson G L 1979 The sea floor morphology seaward of Terre Adelie Antarctica Deut Hydro Zeit 32 2 77 87 Page 140 of 141 Vanney J R Falconer R K L and Johnson G L 1981 in press Geomorphology of the Ross Sea and adjacent oceanic provinces Mar Geol Volokitina L P 1975 Some features of the relief on the underwater margin of East Antarctica Oceanology 15 3 323 326 Watkins N D and Kennett J P 1977 Erosion of deep sea sediments in the Southern Ocean between longitude 70 E and 190 E and contrasts in manganese nodule development Mar Geol 23 1 2 103 111 Weissel J K Hayes D E and Herron E M 1977 Plate tectonics synthesis the displacement between Australia New Zealand and Antarctica since the Late Cretaceous Mar Geol 25 1 3 231 277 Zhivago A V 1961 Marine geophysical and geomorphological researches Proc Sov Antarc Exped Third Antarctic Cruise R V Ob vol 19 Zhivago A V and Evteev S A 1970 Shelf and Marine Terrace of Antarctica Quaternaria 12 89 114 Zhivago A V and Lisitzin A P 1957 New data on the bottom and submarine deposits in the Eastern Antarctic in Russian Izv Akad Nauk S S S R ser geogr 1 19 35 Page 141 of 141
7. Bathymetrie du Pacifique Sud feuilles Mururoa Hao Marquises Tahiti Roroia 1 1 000 000 Centre Oceanologique de Bretagne Brest France Prince R A Schweller W J Ness G E Coulbourn W T Shepherd G L Masias A 1978 Bathymetry of the Peru Chile Trench and Continental Margin 9 sheets Geological Society of America Map Series Rea D K 1976 Changes in the axial configuration of the East Pacific Rise near 6 S during the past 2 m y Journal of Geophysical Research 81 1495 1504 Rea D K 1976 Analysis of a fast spreading rise crest the East Pacific Rise 9 to 12 S Marine Geophysical Researches 2 291 313 Rea D K 1977 Local axial migration and spreading rate variations East Pacific Rise 31 S Earth and Planetary Science Letters 34 78 84 Rea D K 1978 Asymmetric sea floor spreading and a nontransform axis offset the East Pacific Rise 20 S survey area Geological Society of America Bulletin 89 839 844 Page 128 of 141 ANNEX L 12 GEBCO Sheet 5 12 Revised UPDATE NOTE The bathymetry of two regions within the area of GEBCO sheet 5 12 revised have been replaced by the revised bathymetry contained in GEBCO sheets G 06 off equatorial Africa east of 22 W north of the equator and east of 3 E north of 8 S and G 08 south east Atlantic south of 24 S and east of 12 W The revised version of GEBCO sheet 5 12 was published in 1994 by the Canadian Hydrographic Service under the authority
8. Numbered source documents described above except for items 5 6 7 and 9 were contoured in units of uncorrected metres It was necessary to recontour in units of corrected metres using the echo sounding correction tables 3rd edition published in 1980 by the Hydrographic Department of the British Admiralty Page 73 of 141 ANNEX K 4 GEBCO Sheet G 04 NE Atlantic off the Iberian Peninsula Sheet G 04 is a composite of three bathymetric compilations A Bathymetric Chart of the Bay of Biscay published in 1994 and compiled by Jean Claude Sibuet Serge Monti and Guy Pautot Centre de Brest Institut Francais de Recherche de Exploitation de la Mer IFREMER France Sheet 1 01 of the International Bathymetric Chart of the Central Eastern Atlantic IBCEA published in February 2002 by the Instituto Hidrografico Lisbon Portugal Scientific coordinator Jean Rene Vanney Universites Pierre et Marie Curie et Paris Sorbonne France in collaboration with Denis Mougenot Compagnie Generale de Geophysique France Bathymetric compilation of the area between Madeira and the Strait of Gibraltar compiled for GEBCO in 2000 by Peter Hunter Southampton Oceanography Centre SOC United Kingdom Sheet Limits 31 N 48 N 18 W 0 W see below for detailed coverage Scale Bay of Biscay 1 1 2 million IBCEA Sheet 1 01 1 1 million Madeira Strait of Gibraltar 1 500 000 Horizontal datum WGS 84 Contour Units Bathymetric dep
9. USA B J Sloan L A Lawver Japan Oceanographic Data Centre Tokyo Lamont Doherty Earth Observatory New York USA A L Gordon B Huber National Geophysical Data Center Boulder USA National Institute of Polar Research Japan Norwegian Polar Research Institute A Solheim Sevmorgeologia Russia V Krukov V Masolov V Pozdeev Digital data sets used as an aid to interpreting the bathymetry included those referenced in Heidrich B Sievers J Schenke H W and Thiel M 1992 Digitale topographische Datenbank Antarktis Nachr a d Karten u Verm wesen 1 107 p 127 140 Sandwell D T and Smith W H F 1992 Global Marine Gravity from ERS 1 GEOSAT and SEASAT reveals New Tectonic Fabric EOS trans AGU 73 p 133 Fall 1992 AGU Meeting Supplement Schone T 1997 Ein Beitrag zum Schwerefeld im Bereich des Weddellmeeres Antarktika Zur Nutzung von Altimetermessungen des GEOSAT und ERS 1 Ber Polarf 220 Additional background data were extracted from publications especially Ghidella M E and LaBreque J L 1990 Consideraciones sobre la morfologia del Mar de Weddell oeste basados en datos aerogeofisicos In CLAF 1991 p34 44 Hoppe H and Thyssen F 1988 Ice thickness and bedrock elevation in western Neuschwabenland and Berker Island Annals of Glaciology 11 p 42ff Huybrechts P 1992 The Antarctic ice sheet and environmental change a three dimensional modelling study Ber Polarf 99 Japanese A
10. W is only covered between 29 and 42 N Bureau Gravimetrique International Toulouse France in collaboration with Institut Geographique National Paris France and the British Oceanographic Data Centre bathymetric depth in corrected metres Om 200m 500m and at 500m intervals thereafter down to 5000m In some areas additional contours are also present and the digital data set will be found to include contours at the following depths 50m 100m and 700m Page 12 of 141 ANNEX L 6 GEBCO Sheet 5 06 UPDATE NOTE The bathymetry of the area of GEBCO sheet 5 06 in the Indian Ocean i e west of 99 E and south of the line joining the points 99 E 10 N and 105 E 0 N and the Eastern Archipelagic Seas south of 4 N between 115 E to 136 E has been replaced by the revised bathymetry contained in GEBCO sheet G 08 GEBCO sheet 5 06 was published in April 1979 by the Canadian Hydrographic Service under the authority of the IHO and IOC Scientific Coordinator Yoshio Iwabuchi Hydrographic Department Marine Safety Agency Tokyo Japan Cartography by Geoscience Mapping Unit Canadian Hydrographic Service Published Chart GEBCO SHEET 5 06 April 1979 Projection Mercator Scale 1 to 10 million at the Equator Ellipsoid International 1924 Hayford Southern Limit 00 00 N Western Limit 090 00 E Northern Limit 46 47 N Eastern Limit 180 00 E Digitized by Japan Oceanographic Data Center Tokyo Japan in col
11. are made on the quality of digitization including contour labelling geographic registration and conformance with any hard copy charts that may have been published from the compilation Checks are also made against the GEBCO shorelines and any necessary editing is carried out interactively If material is received in hard copy form it is raster scanned externally and then vectorized at BODC In merging new sheets into the GDA careful attention is paid to edge matching the basic GEBCO contours i e 200m 500m and 500m intervals thereafter across the boundaries of the sheets into the surrounding GDA bathymetry so as to maintain a seamless global bathymetry Adjustments are made as necessary taking due account of the underlying trackline control information Intermediate contours are only edge matched if present on both sides of the boundary No attempt is made to edge match tracklines crossing the boundaries a mismatch of tracklines between sheets usually occurs when sheets compiled at different scales are joined and reflects differences in geographic registration accuracy Page 52 of 141 ANNEX J Digitization of the IBCM First Edition INTERNATIONAL BATHYMETRIC CHART OF THE MEDITERRANEAN Published in 1981 by the Head Department of Navigation and Oceanography St Petersburg Russia on behalf of the IOC The IBCM project was conceived in 1972 by participants in the joint OC ICSEM FAO Programme of Cooperative Investigations in the Medi
12. these gaps the interpolation and interpretation has been significantly aided by the dense global coverage of satellite altimetry data from which the sea surface gravity field can be derived A major addition to the GDA is a gridded data base of bathymetry on a grid size of one minute which has been derived primarily from the GEBCO contours and which updates DBDBS5 There has long been pressure on GEBCO to produce a grid that can be used by ocean modellers The grid has been developed by a working group under the leadership of Dr Michael Carron and with significant help from the US Navy Included also is a Gazetteer of undersea feature names that have been researched and approved by the Sub Committee on Undersea Feature Names chaired by Dr Fisher and ably supported by Ing en Chef Michel Huet of IHB A large number of people have been involved in the production of the Centenary GDA freely giving their time on a voluntary basis and often with support of their parent organisation Our Permanent Secretary Dr Robert Whitmarsh and his predecessor Mr Brian Harper have provided invaluable support for the whole GEBCO community To all these give thanks But especially would like to thank Dr Meirion Jones Chairman of the Sub Committee on Digital Bathymetry and formerly of the British Oceanographic Data Centre for driving forward the updating and improvement of the GDA and for his tireless efforts to ensure that it was ready for the Centenar
13. 14 5 15 5 16 5 17 5 18 Scientific Co ordinators responsible for compiling the bathymetry on the sheets of the GEBCO Fifth Edition Scientific Co ordinator Johannes Ulrich Gleb B Udintsev G Leonard Johnson David Monahan Anthony S Laughton David Monahan Anthony S Laughton Yoshio Iwabuchi Jacqueline Mammerickx amp Stuart M Smith Roger C Searle David Monahan G Leonard Johnson Robert L Fisher David Monahan Robin K H Falconer Marie Tharp Jacqueline Mammerickx amp Stuart M Smith Peter Hunter Norman Cherkis Carl Brenner Gleb B Udintsev Robin Falconer amp Jane Handley Dennis E Hayes amp Michael Vogel Robin K H Falconer Marie Tharp Jacqueline Mammerickx amp Isabel Taylor Steven Cande John LaBrecque Philip D Rabinowitz amp Carl Brenner G Leonard Johnson David Monahan Gisle Gr nlie Lawrence W Sobczak G Leonard Johnson Jean Ren Vanney Affiliation Institut f r Meereskunde an der Universit t Kiel Germany Vernadsky Institute of Geochemistry Moscow Russia Office of Naval Research Arlington USA Canadian Hydrographic Service Ottawa Canada IOS Deacon Laboratory Wormley UK Canadian Hydrographic Service Ottawa Canada IOS Deacon Laboratory Wormley UK Hydrographic Department MSA Tokyo Japan Scripps Institution of Oceanography La Jolla USA IOS Deacon Laboratory Wormley UK Canadian Hydrographic Service Ottawa Canada Office of Nav
14. 2 km track spacing for depths from 900 to 2750 meters 8 0 km track spacing for depths over 2750 meters Digital contours from the U S Geological Survey CONMAP data base derived from U S Coast Survey 1 250 000 scale bathymetric maps were used in some areas to fill in small data gaps 2 Contours digitally generated from multibeam surveys conducted by the U S Coast Survey ships WHITING and MOUNT MITCHELL from 1988 to 1992 3 Surveys conducted by the National Imagery and Mapping Agency NIMA ships BARTLETT and KANE from 1983 to 1985 Track spacing 1 8 km 4 Contours digitally generated from a three arc second gridded five beam subset of multibeam surveys conducted by the Scripps Institution of Oceanography ship ATLANTIS II in 1986 Imagery from the side scanning sonar system GLORIA II obtained by the U S Geological Survey was employed in the interpretation of bathymetric contours along portions of the Florida Escarpment IBCCA SHEET 1 03 Scientific Coordinator Troy L Holcombe MGG NGDC Compiler Lisa A Taylor MGG NGDC Page 68 of 141 Digital soundings from the U S National Geophysical Data Center Global Trackline Geophysical Data Base GEODAS Collecting institutions include the Woods Hole Oceanographic Institution Lamont Doherty Earth Observatory of Columbia University U S Geological Survey and the U S Naval Oceanographic Office Sources of detailed surveys and bathymetric contours 1 Soundings from su
15. 490 pp Johnson G L Vanney J R and Hayes D E 1980 in press The Antarctic continental shelf Third symposium on Antarctic Geology and Geophysics Nat Acad of Sciences Wash D C Kennet J P Burns R E et al 1972 Australian Antarctic continental drift palaeo circulation changes and Oligocene deep sea erosion Nature Phys Sci 239 91 51 55 Lisitzin A P and Zhivago A V 1959 Marine geological work of the Soviet Antarctic Expedition 1955 1957 Deep Sea Res 6 1 77 87 Molnar P Atwater T Mammerickx J and Smith S M 1975 Magnetic anomalies bathymetry and the tectonic evolution of the South Pacific since the Late Cretaceous Geophys J Roy Astron Soc 40 383 420 Rose K E 1979 Radio echo studies of bedrock in Marie Byrd Land Antarctica Third Antarctic Geology and Geophysics Symp University of Wisconsin in press Vanney J R Dangeard J and Johnson G L 1972 Contribution a l etude des fonds de la mer de la Scotia et de ses abords Atlantique Austral Rev Geogr Phys Geol dynam 14 5 465 484 Vanney J R and Johnson G L 1976a Geomorphology of the Pacific Continental Margin of the Antarctic Peninsula In C D Hollister C Craddock et al Edit Initial Reports of the Deep Sea Drilling Project vol 35 279 289 Vanney J R and Johnson G L 1976b The Bellingshausen Amundsen basins Southeastern Pacific Major Sea Floor Units and Problems Mar Geol 22 2 71 101
16. 66 W has been replaced by the revised bathymetry contained in GEBCO sheet G 07 The only bathymetry from sheet 5 18 that remains in the GEBCO Digital Atlas is that for the South Pacific region south of 72 S between 160 E and 66 W GEBCO Sheet 5 18 was published in August 1980 by the Canadian Hydrographic Service under the authority of the IHO and IOC Scientific Coordinators G Leonard Johnson Office of Naval Research Arlington U S A and Jean Rene Vanney Universite Pierre et Marie Curie Paris France Cartography by Geoscience Mapping Unit Canadian Hydrographic Service Published Chart GEBCO SHEET 5 18 August 1980 Projection Polar Stereographic Scale 1 to 6 million at 75 S Ellipsoid International 1924 Hayford Southern Limit 90 00 S Western Limit 180 00 W Northern Limit 64 00 S Eastern Limit 180 00 E Digitized by Bureau Gravimetrique International Toulouse France in collaboration with Institut Geographique National Paris France and the British Oceanographic Data Centre Geographic Area Digitized the published chart was only digitized south of 72 S Contour Units bathymetric depth in corrected metres Contours Present 0 200 400 500 600m and at 200m intervals thereafter down to 4400m DATA SOURCES USED IN THE COMPILATION OF SHEET 5 18 CONTOURS Scientific Literature Falconer R K H 1974 Geophysical studies in the southwest Pacific Primarily studies of crustal structure between New Zeal
17. 696 German nautical charts No 1000 INT 1401 1001 INT 1402 241 242 International nautical charts INT 140 Norges Sjokartverk and INT 1403 Hydrografie van Nederlande Contour Charts and Bathymetric Maps Sounding map Norges Sjokartverk 1975 unpublished Bathymetric chart NTNF s Continental Shelf Division 1 1 000 000 1975 Norway Contour chart Norges Sjokarterk No 7016 1 250 000 NTNF s Continental Shelf Division 1974 1975 Data of soviet oceanographic expeditions obtained in accordance with programmes of international co operation Norwegische See Tiefenkarte 1 200 000 Meteor Forschungsergebnisse Reihe A No 12 1972 Special Sounding map from Lamont Doherty Geological Observatory USA unpublished Page 104 of 141 ANNEX L 2 GEBCO Sheet 5 02 MINOR UPDATE NOTE The bathymetry in the area of GEBCO sheet 5 02 north of 64 N has been replaced by the bathymetry contained in GEBCO sheet G 01 GEBCO sheet 5 02 was published in March 1980 by the Canadian Hydrographic Service under the authority of the IHO and IOC Scientific Coordinator Cartography by Published Chart Projection Mercator Scale Ellipsiod Southern Limit Western Limit Northern Limit Eastern Limit Digitized by Geographic Area Digitized Contour Units Contours Present Comments Gleb B Udintsev Institute of Physics of the Earth Moscow USSR Geoscience Mapping Unit Canadian Hydrographic Service G
18. Digitized by Geographic Area Digitized Contour Units Contours Present Comments Jacqueline Mammerickx Stuart M Smith Geological Research Division Scripps Institution of Oceanography La Jolla USA Geoscience Mapping Unit Canadian Hydrographic Service GEBCO SHEET 5 11 March 1980 Mercator Scale 1 to 10 million at the Equator International 1924 Hayford 46 40 S 160 00 W 00 00 S 070 00 W NERC Unit for Thematic Information Systems Reading UK in collaboration with the British Oceanographic Data Centre as for published chart bathymetric depth in corrected metres Om 200m 500m and at 500m intervals thereafter down to 8000m However for many areas intermediate contours are also included and the digital data set will be found to include contours at the following depths 100m 1200m 1600m 1700m 1800m 2200m 2400m and at 100m intervals thereafter down to 5700m The digitized data for this chart were edgematched with that for sheets 5 07 5 10 5 15 and 5 16 with the result that some of the contours at the sheet boundaries may be displaced slightly from their positions on the published chart DATA SOURCES USED IN THE COMPILATION OF SHEET 5 11 CONTOURS SOURCES OF DETAILED SURVEYS Atlantic Oceanographic Laboratory Dartmouth Nova Scotia Canada Centre National pour I Exploitation des Oceans Brest France Hawaii Institute of Geophysics University of Hawaii Honolulu Hawaii USA Lamont Dohe
19. GEBCO decided that the printed sheets of the Fifth Edition should be digitized This proved to be a major task and took the best part of ten years to complete see Annex C The bulk of the work was carried out by the Bureau Gravim trique International in Toulouse and the British Oceanographic Data Centre BODC The resultant data set which covered all the bathymetric contours coastlines and trackline control information depicted on the Fifth Edition sheets provided the basis for establishing what is now called the GEBCO Digital Atlas GDA In 1989 the GEBCO Guiding Committee decided that the GDA should form the base from which future printed editions of GEBCO would be generated However rather than being geared towards the printing schedules of such future editions the updating of the GEBCO through the GDA would be a continual process and the GDA would be published regularly as a product in its own right Without the scale constraints of the printed chart it was envisaged that improved bathymetric compilations would be merged into GEBCO at scales ranging from 1 10 million up to 1 250 000 depending on the density of echo sounding coverage This would be achieved by stitching in so as to maintain the seamless nature of the data set at least for the basic GEBCO contours at 200m 500m and at 500m intervals thereafter The First Release of the GDA was published by BODC in March 1994 on a single CD ROM It included the digitized bathymetric cont
20. Geogr Inst Univ Kiel Bd 3G Purdy G M and Rabinowitz P D 1978 In Melson W G Rabinowitz P D et al Initial Reports of the Deep Sea Drilling Project 45 Washington D C Rabinowitz P D and Ludwig W J 1980 Mar Geol 35 243 275 Rabinowitz P D and Purdy G M 1980 Eastern Kane Fracture Zone unpublished chart Robb J M Schlee J and Behrendt J C 1973 Jour Res US Geol Survey 1 5 563 567 Rona P A 1980 NOAA Atlas 3 US Dept of Commerce NOAA Environmental Res Lab Washington D C 99 pp Rona P A Harbison R N and Bush S A 1974 Mar Geol 16 275 292 Rona P A Schneider E D and Heezen B C 1967 Deep Sea Res 14 625 633 Taylor P T Stanley D J Simkin T and Jahn W 1975 Mar Geol 19 139 157 Uchupi E 1978 Woods Hole Oceanographic Inst Ref No 71 72 2 pp and 10 charts Page 122 of 141 ANNEX L 10 GEBCO Sheet 5 10 MAJOR UPDATE NOTE The bathymetry in the area of GEBCO sheet 5 10 south of 24 S and west of 167 W has been replaced by revised bathymetry contained in GEBCO sheets G 08 and G 09 GEBCO sheet 5 10 was published in March 1982 by the Canadian Hydrographic Service under the authority of the IHO and IOC Scientific Coordinators Cartography by Published Chart Projection Mercator Scale Ellipsoid Southern Limit Western Limit Northern Limit Eastern Limit Digitized by Geographic Area Digitized Contour Units Co
21. J C et al 1984 Morphology and basement structures of the Goban Spur continental margin and the role of the Pyrenean Orogeny Initial Reports of the Deep Sea Drilling Project Volume LXXX p 1153 1165 Washington US Government Printing Office SUB AREA C 47 49 N 9 11 W Compiled by P M Hunter IOS in 1993 Based on conventional echo soundings supported by almost complete GLORIA imagery over the shelf break north of 48 N Good Seabeam coverage in the east and a few Seabeam tracks elsewhere supplied by L Pastouret COB and J C Sibuet COB Page 64 of 141 Reference Pastouret L Beuzart P amp Monti S 1982 Presentation de cartes bathymetriques de la marge continentale armoricaine et celte golfe de Gascogne Bulletin de la Societe Geologique de France 24 p 407 411 SUB AREA D Meriadzek Terrace 47 48 N 7 30 9 20 W Based on a detailed GLORIA survey carried out by RV Farnella in September 1984 complemented by conventional single beam echosoundings Seabeam data were available over the canyon areas supplied by L Pastouret COB and J C Sibuet COB Reference Kenyon N H amp Hunter P M 1985 A long range side scan sonar survey of the Meriadzek Terrace Bay of Biscay Institute of Oceanographic Sciences Report No 20 17pp Page 65 of 141 ANNEX K 3 GEBCO Sheet G 03 Gulf of Mexico and the northern Caribbean Sea INTERNATIONAL BATHYMETRIC CHART OF THE CARIBBEAN SEA AND THE GULF OF ME
22. Mammerickx J Lawver L and Batiza R 1981 in prep Geology of the Louisville Ridge Scripps Institution of Oceanography Carter L 1980 New Zealand Region Bathymetry 1 6 000 000 2nd ed New Zealand Oceanographic Institute misc series 15 Ringis J and Hayes D E 1972 Bathymetry of the Tasman Sea Unpub map Lamont Doherty Geological Observatory Hayes D E and Conolly J R 1972 Morphology of the Southeast Indian Ocean In D E Hayes ed Antarctic Oceanology II Antarctic Research Series Volume 19 American Geophysical Union 125 146 Tharp M 1979 Compilation of Bathymetry Fisher R L 1981 GEBCO 5 09 this series for area 110 E to 116 E Page 124 of 141 SCIENTIFIC LITERATURE Burns R E Andrews J E Van Der Lingen G J Churkin M Galehouse J S Packham G H Davies T A Kennett J P Dumitrica P Edwards A R and Von Herzen R P 1973 Initial Reports of the Deep Sea Drilling Project Leg 21 National Science Foundation University of California La Jolla 931 pp Carter L 1980 New Zealand Region Bathymetry 1 6 000 000 2nd ed N Z Oceanogr Inst Chart Miscellaneous Series 15 Carter L Eade J V Mitchell J S and Rees B J 1977 A Morphologic Guide to the Continental Oceanic Crustal Boundary Around New Zealand New Zealand Oceanographic Institute Summary 13 18 pp Conolly J R 1969 Western Tasman Sea Floor N Z JI Geol Geophys 12 310 43 Davey
23. Mexico Soundings from surveys of the Middle America Trench conducted by the University of Texas between 1977 and 1978 from the research vessel Ida Green and also from surveys conducted by Scripps Institution of Oceanography University of California from the research vessel Thomas Washington in 1972 The spacing between sounding lines is variable between approximately 2km and 4km Page 70 of 141 The coastline is based on the US NIMA s World Vector Shoreline updated with data of the coastline generated from the cartographic series of Mexico topographic maps at a scale of 1 250 000 scale from the DGG of the INEGI IBCCA SHEET 1 06 Scientific Coordinator Jose Luis Frias Salazar DGG INEGI Compilers Marcos Aguilar Benitez Manuel Cruz Pineda DGG INEGI Digital soundings from the U S National Geophysical Data Center Global Trackline Geophysical Data Base GEODAS Sources of detailed surveys and bathymetric contours 1 Soundings from surveys conducted by the University of Hawaii SOEST Hawaii Institute for Geophysics in 1989 from the research ship Moana Wave 2 Campeche Bank and west of Yucatan Basin Soundings from marine geophysical surveys carried out by Oregon State University and the Navy Secretariat of Mexico in 1985 from the research ship Altair 3 Northern edge of Campeche Bank Surveys carried out by the U S National Imagery and Mapping Agency NIMA between 1983 and 1985 from the research vessels Bartlett in
24. Niederjasper and Tilo Schone Vernadsky Institute of Geochemistry and Analytical Chemistry Moscow Russia RV Akademik Boris Petrov Antarctic expeditions GAP 95 and GAP 98 Multibeam data from Hollming Ekhos II system and from narrow beam echo sounder Multibeam surveys by Gleb Udintsev Hans Werner Schenke and Tilo Schone Supporting data and information including analogue and digital sounding data were provided by many other organizations In particular use was made of the following Scientific Databases IHO Data Centre for Digital Bathymetry Boulder Colorado U S National Geophysical Data Centre GEODAS searches on bathymetry November 1992 April 1993 May 1999 October 1999 Antarctic Digital Database Version 3 0 2000 ADD Consortium Scientific Committee on Antarctic Research Scott Polar Research Institute Cambridge UK Marks K M McAdoo D C 1992 Gravity Atlas of the Southern Ocean National Geophysical Data Centre A for Marine Geology and Geophysics Reports MGG 7 Wash D C U S Dept Commerce Sandwell D T Smith W H F 1997 Marine Gravity Anomaly from Geosat and ERS 1 Satellite Altimetry J Geophys Res v 102 p 10 039 10 054 Smith Walter H F Sandwell David T 1997 Global sea floor topography from satellite altimetry and ship depth soundings Science v 227 5334 p 1956 1962 GEBCO Sheets 5 16 and 5 18 bathymetric contours track lines and bedrock contours National Hydrographic
25. Offices Nautical Charts various scales Argentina Russian Federation United Kingdom GEBCO Ocean Plotting Sheets OPS 1 1 000 000 Argentina Republic of South Africa United Kingdom 1 5 000 000 Russian Federation Digital Data Russian Federation United Kingdom United States of America Page 93 of 141 Scientific Publications Gracia E Canals M LiFarran M Sorridas J Pallas R 1997 Central and Eastern Bransfield Basins Antarctica from high resolution swath bathymetry data Antarctic Science 9 2 p 168 180 LawverL A Sloan B J Barker D H N Ghidella M von Herzen R P Keller R A Klinkhammer G P 1996 Distributed Active Extension in Bransfield Basin Antarctic Peninsula Evidence from Multibeam Bathymetry GSA Today v 6 No 11 p 1 7 16 17 Schenke H W Dijkstra S Niederjasper F Hinze H Hoppmann B Schone T 1998 The New Bathymetric Charts of the Weddell Sea AWI BCWS In Ocean Ice and Atmosphere Interactions at the Antarctic Continental Margin Stanley S Jacobs and Raymond F Weiss eds Washington DC American Geophysical Union 1998 Antarctic Research Series Vol 75 371 380 Tectonic Map of the Scotia Arc 1985 1 3 000 000 BAS Misc 3 Cambridge Survey Vegas R Acosta J Uchip E 1995 Continental Oceanic Crustal Transition in the Bransfield Trough and the South Scotia Ridge Antarctica preliminary results in E Banda et al eds Rifted Ocean C
26. Soc of Amer Bull 87 793 808 Page 108 of 141 ANNEX L 4 GEBCO Sheet 5 04 MAJOR UPDATE NOTE The bathymetry in the area of GEBCO Sheet 5 04 from 47 N to 64 N 37 W to 6 E has been replaced by the revised bathymetry contained in GEBCO Sheet G 02 North of 64 N it has been replaced by the revised bathymetry of GEBCO sheet G 01 In the narrow border 46 40 N to 48 N from 0 to 13 W the bathymetry has been replaced by data from GEBCO Sheets G 02 and G 04 GEBCO sheet 5 04 was published in April 1978 by the Canadian Hydrographic Service under the authority of the IHO and IOC Scientific Coordinators Cartography by Published Chart Projection Mercator Scale Ellipsoid Southern Limit Western Limit Northern Limit Eastern Limit Note Digitized by Geographic Area Digitized Contour Units Contours Present Anthony S Laughton Institute of Oceanographic Sciences Wormley United Kingdom and David Monahan Canadian Hydrographic Service Ottawa Canada Geoscience Mapping Unit Canadian Hydrographic Service GEBCO SHEET 5 04 April 1978 1 to 10 million at the Equator International 1924 Hayford 46 40 N 095 00 W 72 00 N 000 00 E The area from 90 to 95 W is only covered between 55 and 65 N Bureau Gravimetrique International Toulouse France in collaboration with Institut Geographique National Paris France and the British Oceanographic Data Centre as for published c
27. The Centenary Edition of the GEBCO Digital Atlas GDA is published as a pair of CD ROM discs discs 1 and 2 and contains three main components viz a set of User Guides the GDA data sets and a GDA Software Interface Three User Guides are provided i User Guide to the GDA and its data sets this volume in file MANUAL PDF on disc 1 ii User Guide to the GEBCO One Minute Grid in file GRID GRIDHELP PDF on disc 1 iii User Guide to the GDA Software Interface in file HELP PDF on disc 1 All three are accessible using the Adobe Acobat Reader either directly or through the help menu of the GDA Software Interface The following data sets are incorporated in the Centenary Edition a the digitised bathymetric contours coastlines and trackline control of the October 2002 version of the GEBCO Digital Atlas Based primarily on the digitised GEBCO Fifth Edition it also includes completely new bathymetry for the Arctic and Indian Oceans as well as significant updates for areas of the North Atlantic the Weddell Sea and the area around New Zealand A binary version is stored on disc 1 for user selected display export via the GDA Software Interface while an ASCII version is stored on disc 2 for users requiring direct access b the GEBCO One Minute Bathymetric Grid Based primarily on the bathymetric contours of the October 2002 version of the GDA it also incorporates the IGBP GLOBE one minute grid for land elevations Stored o
28. areas 1 135 to 139 E 0 N 2 150 to 151 E 0 N DATA SOURCES USED IN THE COMPILATION OF SHEET 5 10 CONTOURS CONTOUR CHARTS AND BATHYMETRIC MAPS Mammerickx J Fisher R L Emmel F J and Smith S M 1977 Bathymetry of the East and Southeast Asian Seas 1 6 442 194 Geological Soc America Maps amp Charts Series MC 17 Kroenke L W Moberly Jr R Winterer E L and Heath G R 1971 Bathymetry of the Ontong Java Plateau In Lithologic Interpretation of Continuous Reflection Profiling Deep Sea Drilling Project Vol VII Part 2 p 11717 Hawaii Institute of Geophysics University of Hawaii Mammerickx J Chase T E Smith S M and Taylor I L 1971 1974 Bathymetry of the South Pacific in fathoms interpolated to metres by D Monahan IMR Technical Reports 44A 45A amp 46A Scripps Institution of Oceanography La Jolla California Winterer E L Lonsdale P P Matthews J L and Rosendahl R B Bathymetry of the Manihiki Plateau In Structure and Acoustic Stratigraphy of the Manihiki Plateau Deep Sea Research 21 p 793 814 Hawkins J W 1974 Geology of the Lau Basin A Marginal Sea Behind the Tonga Arc In Geology of Continental Margins C Burke amp C Drake editors p 505 520 New Zealand Oceanographic Institute 1971 Oceanic Chart Series 1 1 000 000 Bathymetry of the Tonga Trench Halunen Jr A J 1979 Ph D Thesis Columbia University Charts of the North Fiji Basin Hawkins J
29. between 5 W to 166 E It will include the compilation and interpretation of all available bathymetric magnetic and satellite derived gravity data from Africa Asia Australia south to Antarctica The basic source document used for the bathymetric contouring was the 1950 1995 compilation of echo sounding data maintained by Dr Fisher at SIO on a set of 240 or so hard copy oceanic scale 4 inches to 1 degree of longitude Mercator projection plotting sheets These were augmented in very large degree by further soundings contributed by academic and government agency sources as listed below These sources contributed data either as hard copy plotting sheets typically 1 1 million scale Mercator plots or as digital files of cruise navigation and soundings accompanied by standard velocity correction notations The digital files were plotted out for Dr Fisher by Virginia Wells and Uta Albright at SIO s Geological Data Center During the compilation the soundings were compared and checked for recording errors and for pre satellite navigated tracks slight track adjustments were made as necessary to minimize crossover discrepancies A compilation of tracklines corrected for digitising errors and omitting segments without soundings was compiled concurrently on a parallel set of hard copy plotting sheets at the same scale The sounding data were hand contoured by geological interpretation by Dr Fisher sheet by sheet employing multiple cruise sounding
30. compiled sheet Edge matching was carried out across the sheets to ensure the digitized data provide a seamless bathymetry across the globe Thus digitized contours at sheet boundaries may not always accord with those on the printed sheets although any adjustments made were carried out taking due account of the underlying trackline control information The two polar sheets 5 17 and 5 18 were only digitized to the 72 latitude i e they were not digitized where they overlapped adjacent Mercator sheets For sheet 5 06 in the Western Pacific the digital contours and coastline for the area from 100 E to 180 E were taken directly from a digital data base maintained by the Japan Oceanographic Data Center Tokyo An earlier version of this data base had in fact formed the basis for the published sheet Rather than digitize the outdated version of 5 12 BODC collaborated in the production of the revised version of this sheet The revised contouring of various sections of the sheet was carried out by scientists in the USA Russia New Zealand and the UK and following review by two nominated GEBCO experts their hand drawn contours were sent to BODC for digitizing and for compiling into a single seamless sheet The contents of the digitized file were later used as the base from which a revised sheet was published by the Canadian Hydrographic Service in 1994 The coastline was digitized from the Fifth Edition sheets It was based on the Carte G n ra
31. contains the supporting documentation to accompany the nine charts used to update GEBCO in the Centenary Edition of the GEBCO Digital Atlas Annex K 1 Sheet G 01 Arctic Ocean Annex K 2 Sheet G 02 North east Atlantic off the British Isles Annex K 3 Sheet G 03 Caribbean Sea and the Gulf of Mexico Annex K 4 Sheet G 04 North east Atlantic off the Iberian Peninsula Annex K 5 Sheet G 05 Mid Atlantic Ridge to North west Africa Annex K 6 Sheet G 06 Central Eastern Atlantic Annex K 7 Sheet G 07 Weddell Sea and the Bransfield Strait Annex K 8 Sheet G 08 Greater Indian Ocean Annex K 9 Sheet G 09 Waters around New Zealand Page 55 of 141 ANNEX K 1 GEBCO Sheet G 01 Arctic Ocean INTERNATIONAL BATHYMETRIC CHART OF THE ARCTIC OCEAN IBCAO Contours computed from Version 1 0 of the IBCAO grid dated July 2001 Authors Martin Jakobsson University of New Hampshire USA Norman Cherkis Five Oceans Consultants USA formerly of the US Naval Research Laboratory John Woodward Royal Danish Administration of Navigation and Hydrography Ron Macnab Geological Survey of Canada and Bernard Coakley University of Alaska Fairbanks USA Contributions by Members of the IBCAO Editorial Board Sheet limits Horizontal Datum Scale Contour Units Contours present Coastline Source Reference Jennifer Harding Geological Survey of Canada Hans Werner Schenke and Martin Klenke Alfred Wegener Institute G
32. gridded version of the bathymetry followed by manual adjustment as appropriate and included in the data set As a result of this about one third of the 500m 1500m 2500m etc contours on IBCEA Sheets 1 01 to 1 04 were generated by BODC with about two thirds generated for Sheets 1 05 to 1 09 For large areas of IBCCA sheets 1 01 1 02 1 03 1 05 and 1 09 trackline control is shown in terms of survey boxes rather than as individual sounding points or tracklines These are areas of high sounding density and occur particularly in the northern half of the Gulf of Mexico around the Yucatan peninsula and the Atlantic seaboard off Florida Further information on these survey areas may be found in the GEBCO Digital Atlas DATA SOURCES IBCCA SHEET 1 01 Scientific Coordinator Troy L Holcombe MGG NGDC Compiler Lisa A Taylor MGG NGDC Digital soundings from the U S National Geophysical Data Center Global Trackline Geophysical Data Base GEODAS Collecting institutions include the Institute for Geophysics University of Texas Lamont Doherty Earth Observatory of Columbia University U S Coast Survey and the U S Naval Oceanographic Office Sources of detailed surveys and bathymetric contours 1 Soundings from surveys conducted by the U S National Oceanic and Atmospheric Administration National Ocean Service Coast Survey Track spacing varies with depth 0 1 to 0 8 km track spacing for depths from 0 to 200 meters 0 8 to 1 6 km tra
33. longitude is stored in the range 180 to 180 with east positive and west negative When data are exported to this format from the GDA Software Interface it is also possible for the user to specify that longitude should be stored in the range 0 to 360 Ordering contiquity of vectors CD ROM ASCII files Within each file the vector streams are stored in ascending order of their feature code value ICODE In general the GEBCO coastline and the basic GEBCO contours 200m 500m and at 500m intervals thereafter are continuous i e without gaps and should be contiguous within the geographic area of each ASCII file For closed contours the first point of the vector should have the same coordinates as the last point Likewise the IBCM data should be contiguous within their sheet boundaries SCAR coastlines are only contiguous along the length of each feature within the sheet limits of the original source material contiguity breaks down when the feature code changes Through the GDA Software Interface Within the GDA the vector data are split into ten degree squares and on export the vectors are ordered first by ten degree square and then by feature code If required the user can request output ordered only by feature code but should be aware that the ordering process creates temporary disc files on the user s PC Exporting ordered data for a large area may therefore require a large amount of free disc space In splitting the vectors i
34. ngdc noaa gov mgg ibcao International Bathymetric Chart of the Mediterranean IBCM http www ngdc noaa gov mgg ibcm International Bathymetric Chart of the Caribbean Sea amp Gulf of Mexico IBCCA http www ngdc noaa gov mgg ibcca International Bathymetric Chart of the Central Eastern Atlantic IBCEA http www ngdc noaa gov mgg ibcea IGBP Global Land One kilometer Base Elevation GLOBE Project http www ngdc noaa gov seg topo globe shtml IHO Data Centre for Digital Bathymetry http www ngdc noaa gov mqq bathymetry iho html GEODAS World Geophysics Database http www ngdc noaa gov mgg geodas Names of Undersea Features inc IHO IOC Gazetteer http Awww ngdc noaa gov mgg gebco underseafeatures html Generic Mapping Tools GMT software http gmt soest hawaii edu netCDF format http www unidata ucar edu packages netcdf ESRI Shapefile format http www esri com library whitepapers pdfs shapefile pdf Page 6 of 141 Contents Preface Acknowledgements Copyright and Attribution Useful Websites Centenary Edition of the GEBCO Digital Atlas 1 0 Introduction 2 0 Contents of the Centenary Edition 3 0 Data sets included in the Centenary Edition 3 1 GEBCO Contours and Trackline Control 3 2 GEBCO One Minute Grid 3 3 Coastlines 3 4 Geographic Names 3 5 Inventory of data held at the IHO DCDB 3 6 Echo sounding correction tables 4 0 Main Features of the GDA Software Interface 5 0 Exporting Data from the
35. of the IHO and IOC The sheet was published directly from material digitized by BODC from contour compilations provided in hard copy form by the scientific coordinators Scientific Coordinators Digitized by Geographic Area Digitized Contour Units Contours Present Norman Cherkis Naval Research Laboratory Washington USA Gleb Udinstev Vernadsky Institute of Geochemistry Geochemistry Moscow Russia Robin Falconer and Jane Handley GeoResearch Associates Waikanae New Zealand Carl Brenner Lamont Doherty Geological Observatory Columbia University New York and Peter Hunter Institute of Oceanographic Sciences Deacon Laboratory Wormley UK The British Oceanographic Data Centre The digital data covers the area 70 W to 20 E 7 N to 50 S and was prepared from bathymetric contours compiled on Mercator charts at a scale of 1 5 737 447 at the equator bathymetric depths in corrected metres 0 200m 500m and at 500m intervals thereafter down to 7000m However in some areas bathymetric contours at the following depths are found 10m 20m 40m 50m 60m 80m 100m 300m 400m 1200m and at 200m intervals thereafter to 6000m Additional contours are also found at 1300m 2300m and at 100m intervals from 2900m down to 6100m Originators of Bathymetric Contours 1 Norman Cherkis 00 00 S to 40 00 S 70 00 W to 20 00 E 2 Carl Brenner 40 00 S to 50 00 S 70 00 W to 20 00 E 3 Gleb Udintsev 00 00 N to 05 00
36. of the Oceanographic Museum at Monaco in 1910 Prince Albert called together an international committee of experts to discuss the production of a Second Edition of GEBCO The first sheets of the Second Edition were published in 1912 but the last did not appear until 1930 World War broke out when only a part of the series had been printed and Prince Albert died in 1922 Dr Jules Richard Director of the Oceanographic Museum supervised the production of the remaining sheets of the series according to the wishes expressed in the Prince s will For the Second Edition the number of soundings had increased to 30 000 Dr Richard writing in 1930 remarked The second edition 1912 1930 is much more complete than the first The assembled coloured sheets form a magnificent chart of unique type It is particularly interesting as an ensemble it shows up in a striking fashion the gaps in our knowledge of the relief of the sea bottom It shows us clearly what has yet to be done to fill these gaps the present chart must be retained it must be completed little by little and thus brought to perfection The gaps are enormous some of them are several hundreds of thousands of square kilometres in extent In these days echo sounding will make it easier to fill them up than in the past for a vessel can take soundings while underway Page 26 of 141 Almost up to World War II all soundings in the deep ocean were discrete wire soundings obtained la
37. shown on the printed chart 1 U S National Oceanic and Atmospheric Administration National Ocean Service surveys Track spacing for this area is 0 25 to 2 8 km 2 U S National Oceanic and Atmospheric Administration National Ocean Service surveys Trackline spacing for this area is 0 25 to 1 5 km 3 U S Naval Oceanographic Office survey trackline spacing 0 8 to 1 0 km The survey was completed by the USS Prevail in 1962 4 U S Naval Oceanographic Office survey trackline spacing 0 8 to 1 0 km The survey was completed by the USS Sheldrake in 1961 Page 69 of 141 Bathymetry for survey areas 1 and 2 was derived from surveys conducted between 1983 and 1984 Most of the surveys were conducted by the U S National Oceanic and Atmospheric Administration National Ocean Service survey ship WHITING Tracklines shown for the remaining area are from Digital data files of the U S National Geophysical Data Center Primary sources include the U S Navy Woods Hole Oceanographic Institution Lamont Doherty Geological Observatory Scripps Institution of Oceanography U S Geological Survey and the Defense Mapping Agency Random tracks from the U S Naval Oceanographic Office Mid Ocean Dynamics Experiment MODE I Region Bathymetry Chart 1 at a scale of 1 500 000 compiled by Patricia A Bush published by the National Oceanic and Atmospheric Administration National Ocean Service for the Environmental Research Laboratories Atlant
38. the 4600m contour westwards to 30 W is contoured at 100m intervals West of about 30 W the bathymetry is contoured at 500m intervals The area of IBCEA sheet 1 06 has contours at 50m 100m 200m and at 200m intervals thereafter including intermediate 500m interval contours NIMA World Vector Shoreline at a scale of 1 250 000 Geographic Coverage Digitization Reference 18 N 20 N 40 W 30 W 19 14 N 20 N 24 58 W 14 W 20 N 25 53 N 47 W 14 W 25 53 N 30 N 47 W 20 W 30 N 32 N 47 W 39 30 W 30 N 31 11 N 31 13 W 20 W 31 11 N 32 N 30 W 20 W 32 N 34 30 N 30 W 21 W 34 30 N 35 N 30 W 23 33 W Contours digitized by BODC with tracklines submitted by SOC in digital form IBCEA sheet 1 06 contours digitized by SHOM with trackline control provided in the form of sounding points IBCEA Sheet 1 06 was published by SHOM on behalf of the IOC in October 2000 Scale of 1 1 million with contours at 50m 100m 200m and at 200m intervals thereafter Sheet limits 19 14 N 25 53 N 24 58 W 14 28 W Page 78 of 141 PREPARATION OF GEBCO SHEET G 05 The bathymetry was compiled by Peter Hunter at SOC in a series of charts at a range of scales from 1 750 000 to 1 1 250 000 In general the contouring was carried out at intervals of 100m although west of about 30 W the interval was increased to 500m Copies of the hand
39. the US Defense Mapping Agency DMA released its World Vector Shoreline WVS the only coastline able to satisfy the GEBCO criteria Acting on the advice of its Subcommittee the GEBCO Guiding Committee agreed that WVS should be adopted as the standard coastline for future use in GEBCO and the DMA generously gave GEBCO permission to use WVS in the GEBCO Digital Atlas The WVS has also been adopted as the standard coastline for use in IOC s Regional Ocean Mapping Projects A description of the WVS may be found in Soluri E A and V A Woodson 1990 World Vector Shoreline International Hydrographic Review Vol LXVII 1 p27 36 The WVS was developed by the DMA as a digital data file at a nominal scale of 1 250 000 and referenced to the World Geodetic System WGS 84 datum Worldwide coverage of the data set was completed in July 1989 working to a specification that 90 of all identifiable shoreline features should be located within 500 metres i e 2mm at 1 250 000 of their true geographic position with respect to the WGS 84 datum The main source material for the WVS was DMA s Digital Landmass Blanking DLMB database which was derived primarily from the Joint Operations Graphics and coastal nautical charts produced by DMA The DLMB data consisted of a land water flag file on a 3 by 3 arc second interval geographic grid This raster database was converted into vector form to create WVS and explains the 3 arc second stepping interval apparen
40. using the GDA Software Interface in a similar manner to that outlined above for oceanic islands Ports Cities and Antarctic Stations The GDA includes a geographically referenced list of all ports and cities annotated on the sheets of the GEBCO Fifth Edition Their names are taken directly from these sheets and their geographical coordinates were taken from the Gazetteer in the Times Atlas of the World Comprehensive Edition These coordinates were checked relative to the digitised version of the GEBCO Fifth Edition coastline viewed through the GDA Software Interface Page 48 of 141 The GDA also includes a geographically referenced list of scientific stations operating in Antarctica south of 60 S during the Antarctic winter of 1991 The list covers stations occupied by the member nations of the ICSU Scientific Committee on Antarctic Research and was reproduced from SCAR Bulletin No 103 October 1991 Page 49 of 141 ANNEX H Echo Sounding Correction Tables Measurements of seafloor depths using echo sounding techniques depend on knowledge of the mean velocity of sound in the water column between the echo sounding device and the seafloor This in turn is dependent on the temperature and salinity down the water column and these characteristics vary across the world s oceans Most modern echo sounders assume a sound speed of 1500 m s while some earlier versions assume 800 fm s 1463 m s Since 1929 when the First Edition of Matthews Tables
41. were then converted from polar stereographic co ordinates to geographic latitude and longitude co ordinates The bathymetric contour data set was filtered to cut down on the volume of points using the Douglas Peucker algorithm This data set was then submitted to BODC for inclusion in the GEBCO Digital Atlas Final editing of the contour data set to remove any small artefacts that were generated during the gridding process was carried out at BODC by Norman Cherkis in July 2001 He was also responsible for edge matching the contours with adjacent sheets in the GEBCO Digital Atlas The digital coastline data sets were also added to the contour data set at BODC Trackline control information was provided by Martin Jakobsson in the form of a digital file containing the position of sounding points in the IBCAO database Page 57 of 141 DATA SOURCES Echo sounding data archives of US National Geophysical Data Centre US Naval Research Laboratory Canadian Hydrographic Service and Royal Danish Administration of Navigation and Hydrography US Navy and British Royal Navy submarine cruises 1957 88 Multibeam data collected by Norwegian Petroleum Directorate Multibeam data from RV Polarstern 1990 1994 1995 1997 Swedish ice breaker Oden cruises 1991 1996 US SCICEX project single beam bathymetry six submarine missions 1993 1999 Canadian Hydrographic Service 1979 GEBCO Sheet 5 17 map scale 1 6 000 000 Cherkis N Z H S Fleming M D Max P R V
42. within territorial waters Page 51 of 141 j updated compilations and supporting material will be submitted for review by a GEBCO approval panel which will comprise the compiler and two independent experts The review team will report back to the GEBCO Officers Adherence to the above principles should ensure that at any given time a high quality seamless global bathymetric chart of GEBCO basic contours can be output from the GDA In general it is envisaged that the geographic coverage of newly inserted compilations will normally but not exclusively be in excess of a minimum size of 5 by 5 or its equivalent area It is anticipated that compilations at the larger scales will include progressively increased numbers of intermediate contours possibly with intervals as small as 20m at the largest scale The contour interval will in general be governed by the sounding density and the smoothness of the topography The use of digital techniques will enable seafloor relief to be stored at high resolution where appropriate without compromising the facility to produce smaller scale seamless charts of the GEBCO basic contours It is planned that the generalisation of larger scale compilations being input into the GDA will be kept to minimum so as to avoid loss of information The GDA is updated and maintained at the British Oceanographic Data Centre BODC by the GDA Manager Pauline Weatherall As each new compilation is received careful checks
43. 000m DATA SOURCES USED IN THE COMPILATION OF SHEET 5 14 CONTOURS Contour Charts and Bathymetric Maps Johnson G L and Vanney J R 1980 GEBCO 5 18 This series Carter L 1980 New Zealand Region Bathymetry 1 6 000 000 2nd ed New Zealand Oceanographic Institute misc series 15 Page 131 of 141 Hayes D E and Conolly J R 1972 Morphology of the Southeast Indian Ocean In D E Hayes ed Antarctic Oceanology II Antarctic Res Ser 19 Amer Geophys Union 125 145 Ringis J and Hayes D E 1972 Bathymetry of the Tasman Sea Unpub map Lamont Doherty Geology Observatory Mammerickx J Chase T E Smith S M and Taylor I L 1974 Bathymetry of the South Pacific Scripps Institution of Oceanography Scientific Literature Carter L Eade J V Mitchell J S and Rees J 1977 A morphologic guide to the continental oceanic crustal boundary around New Zealand New Zealand Oceanographic Inst Summary 13 18 pp Christoffel D A and Falconer R K H 1972 Marine magnetic measurements in the southwest Pacific Ocean and the identification of new tectonic features In D E Hayes Ed Antarctic Oceanology II Antarctic Res Ser 19 Amer Geophys Union 187 200 Christoffel D A and Falconer R F 1973 Magnetic measurements in the Macquarie Ridge region In Oceanography of the South Pacific 1972 R Fraser compiler New Zealand National Committee for UNESCO 233 240 Davey F J 1977 Marine Se
44. 02 by the Instituto Hidrografico Lisbon Portugal c a bathymetric compilation of the area between Madeira and the Strait of Gibraltar compiled for GEBCO in 2000 by Peter M Hunter Southampton Oceanography Centre U K G 05 Mid Atlantic Ridge to North west Africa see Annex K 5 Compiled for GEBCO in 2002 by Peter M Hunter Southampton Oceanography Centre U K and including IBCEA Sheet 1 06 published by the Service hydrographique et oc anographique de la marine SHOM in Brest France G 06 Central Eastern Atlantic see Annex K 6 Updated bathymetry for this area comprises IBCEA Sheets 1 08 to 1 12 published by the Service hydrographique et oc anographique de la marine SHOM in Brest France and delivered to GEBCO in digital form G 07 Weddell Sea and the Bransfield Strait see Annex K 7 An updated bathymetric chart for the Weddell Sea was provided to GEBCO by Hans Werner Schenke and his co workers at the Alfred Wegener Institute for Polar and Marine Research Bremerhaven Germany It also includes contributions from Gleb B Udintsev and his colleagues at the Vernadsky Institute of Geochemistry and Analytical Chemistry Moscow G 08 Greater Indian Ocean see Annex K 8 This is by far the largest contribution to the updating of GEBCO covering almost a quarter of the world s oceans and extending out to 12 W in the Atlantic and to 170 E in the Pacific It was compiled by Dr Robert L Fisher at the Scripps Institution of Oceanogr
45. 111 2133 Fleisher U 1969 Deutsch Hydrog Zeit 22 205 208 Fleisher U 1971 Mar Geoph Res 1 314 327 Fleisher U Holzkamm F Vollbrecht K and Voppel D 1974 Deutsch Hydrog Zeit 27 3 97 113 Fleischer U Korschunow A Shulz G and Vogt P R 1973 Meteor Forsch Ergebnisse C 13 64 84 Fleming H S Cherkis N Z and Heirtzler J R 1970 Mar Geoph Res 1 37 45 Grant A C 1975 Can Soc Petroleum Geol Mem 4 411 431 Page 10 of 141 Henderson G 1975 Offshore Technology Conf Paper OTC 2223 Conf Johnson G L and Campsie J 1974 Norsk Polarinstitutt Arbok Oslo 1976 69 81 Johnson G L Sommerhoff G and Egloff J 1975 Marine Geology 18 175 196 Laughton A S Roberts D G and Graves R 1975 Deep Sea Research 22 791 810 Meyer O Voppel D Fleischer U Closs H and Gerke K 1972 Deutsch Hydrog Zeit 25 5 193 201 Monahan D and Macnab R F 1974 Geol Surv Can Paper 74 30 207 216 Olivet J L Le Pichon X Monti S and Sichler B 1974 J Geophys Res 79 14 2059 2072 Roberts D G 1975 Phil Trans Roy Soc A 278 447 509 Talwani M Poppe B Hastings J and Aitken T 1974 LDGO technical report Lamont Doherty Survey of the World Ocean Talwani ed Talwani M Windisch C C and Langseth M G 1971 J Geophys Res 76 2 473 517 Ulrich J 1962 Deutsch Hydrog Zeit 6 15 pp Ulrich J 1960 Kie
46. 41 Schematic Diagram to illustrate the various types of coastline around Antarctica c grounding line gt g ice shelf front Grounded ice Floating ice shelf ice coastline rock coastline grounding line rock against ice shelf iceberg tongue floating glacier tongue ice shelf front A rock outcrop pe ice covered land Ice covered floating ice land with rock outcrops Page 39 of 141 In the Antarctic the land surface may manifest itself either as rock or as grounded ice In the coastal zone where there are ice shelves the interface between the two types of permanent ice is represented by a grounding line This is the line along which the inland ice sheet ceases to be grounded on bedrock and becomes permanent floating ice i e ice shelf It should be noted that the grounding line does not correspond to the zero contour There are 8 basic types of coastline represented around Antarctica a ice coastline b rock coastline c grounding line d rock against ice shelf e iceberg tongue f floating glacier tongue g ice shelf front h ice rumples It may be noted that a b c d and h represent the landward limits of seawater in c and d the seawater lies beneath an ice shelf before reaching its landward limit On the other hand e f g represent the seaward limits of permanent floating ice as such they are more susceptible to dynamic change Update note ice rumples wer
47. 46 57 9 Page 86 of 141 Lancelot Y Seibold E Cepek P Dean W E Eremeev V Gardner J Jansa L F Johnson D Krashninnikov V Pflaumann U Rankin J G Trabant P and Bukry D 1977 Site 366 Sierra Leone Rise In Initial Reports of the Deep Sea Drilling Project Vol XLI 21 161 McMaster R L Lachance T P Ashraf A and de Boer J 1971 Geomorphology structure and sediments of the continental shelf and upper slope off Portuguese Guinea Guinea and Sierra Leone In F M Delany Ed pp 109 19 McMaster R L de Boer J and Ashraf A 1970 Magnetic and seismic reflection studies on continental shelf off Portuguese guinea guinea and Sierra Leone West Africa American Association of Petroleum Geologists Bulletin 54 158 67 McMaster R L Christofferson E and Ashraf A 1975 Structural framework of continental shelf and slope off southwestern Sierra Leone West Africa American Association of Petroleum Geologists Bulletin 59 2161 71 McMaster R L Ashraf A and de Boer J 1973 Transverse continental margin fracture zone off Sierra Leone Nature London 244 93 94 Martin L 1971 The continental margin from Cape Palmas to Lagos bottom sediments and submarine morphology In F M Delany Ed pp 82 95 Mascle J BornHold B D and Renard V 1973 Diapiric structures off Niger delta American Association of Petroleum Geologists Bulletin 57 9 1672 1678 Mascle J Mari
48. Aires Argentina University of Birmingham P O Box 363 Birmingham UK Hydrographic Office Ministry of Defence Taunton TA1 2DN UK Scientific Literature Barker P F 1972a A spreading centre in the East Scotia Sea Earth and Planet Sci Lett 15 123 132 Barker P F 1972b Magnetic lineations in the Scotia Sea Adie R J Ed Antarctic Geology and Geophysics Universitetsforlaget Oslo 17 26 Barker P F A possible southern extension of the South Sandwich Arc during the Mid Cenozoic Antarctic Geoscience Univ of Wisconsin Press Barker P F and Burrel J 1977 The opening of Drake Passage Marine Geology 25 15 34 Barker P F and Griffiths D H 1972 The evolution of the Scotia Ridge and Scotia Sea Phil Trans Roy Soc London Ser A 271 151 183 Barker P F et al 1976 Evolution of the Southwestern Atlantic Ocean Basin Results of Leg 36 Deep Sea Drilling Project Initial Reports of the Deep Sea Drilling Project 36 US Government Printing Office Washington D C 993 1014 Barrett D M 1977 Agulhas Plateau off southern Africa A geophysical study Geol Soc Amer Bull 88 749 763 Barron E M Harrison C G A and Hay W W 1978 A revised reconstruction of the Southern continents EOS Trans Amer Geophys Union 59 436 449 Bergh H W 1971 Sea floor spreading in the southwest Indian Ocean J Geophys Res 76 6276 Bergh H W 1977 Mesozoic sea floor off Dronning Maud
49. Atlantique nord est C R Acad Sc Paris Serie Il 300 4 145 149 Bathymetric map scale 1 2 4 million published by IFREMER France Above two charts revised with data from Service Hydrographique et Oceanographique de la Marine SHOM France GEBCO Plotting Sheets 43 and 60 DATA SOURCES USED FOR GEBCO SHEET G 04 AREA C Madeira Strait of Gibraltar Contours were based on collected oceanic soundings from the following sources a GEBCO Plotting Sheets of Collected Oceanic Soundings up to 1983 Scale 1 1 000 000 Service Hydrographique et Oceanographique de la Marine SHOM Brest France b GEODAS Marine Trackline Geophysical Dataset up to 1998 National Geophysical Data Center NOAA Boulder U S A c Southampton Oceanography Centre formerly Institute of Oceanographic Sciences up to 1998 Natural Environment Research Council U K The following was widely consulted Hunter P M Searle R C and Laughton A S 1983 Bathymetry of the Northeast Atlantic Sheet 5 Continental Margin Off West Africa Scale 1 2 400 000 Admiralty Chart C6570 Hydrographer of the Navy Taunton U K Detailed surveys were included from the following sources Ampere Seamount scales 1 50 000 and 1 100 000 Unpublished chart Alfred Wegener Institute Bremerhaven Germany Auzende J M Monti S and Ruellan E 1983 Carte Bathymetrique de L Escarpment de El Jadida Mazagan scale 1 100 000 Centre National pour l Exploitation des
50. Atmospheric Administration 1980 Bathymetric Chart of the Caribbean scale 1 2 500 000 U S Naval Oceanographic Office surveys trackline spacing 1 10 km Adapted from bathymetric contours by James E Matthews and Troy L Holcombe compiled at a scale of 1 1 000 000 and published at a scale of 1 2 000 000 in Matthews J E and Holcombe T L 1976 Regional Geological Geophysical Study of the Caribbean Sea Navy Ocean Area NA 9 1 Geophysical Maps of the Eastern Caribbean U S Naval Oceanographic Office Reference Publication Rp 3 U S Naval Oceanographic Office surveys trackline spacing 1 10 km U S Naval Oceanographic Office surveys trackline spacing 0 05 to 2 km Bathymetry for survey areas 3 and 4 is adapted from bathymetric contours by Julian C Cooey 1978 in Structure and Stratigraphy of the Offshore Margin of the Dominican Republic unpublished M S Thesis University of Southern Mississippi U S National Oceanic and Atmospheric Administration National Ocean Service surveys trackline spacing 0 025 to 0 3 km U S National Oceanic and Atmospheric Administration National Ocean Service surveys trackline spacing 0 3 to 0 6 km U S National Oceanic and Atmospheric Administration National Ocean Service surveys trackline spacing 0 6 to 1 5 km Bathymetry for survey areas 5 6 and 7 is derived from 159 surveys conducted between 1900 and 1988 Most of the surveys were conducted between 1968 and 1988 by the U S National Ocean
51. Centenary Edition 5 1 Accessing the GEBCO One Minute Grid 5 2 Exporting vector data using the GDA Software Interface 5 3 Directly accessible vector data in ASCII format Annexes Historical background to GEBCO Production of the GEBCO Fifth Edition Digitization of the GEBCO Fifth Edition World Vector Shoreline WVS SCAR Coastline of Antarctica IHO Data Centre for Digital Bathymetry DCDB Geographic Names in the GEBCO Digital Atlas Echo Sounding Correction Tables Procedures for updating GEBCO contours Digitization of the IBCM First Edition Supporting Documentation for Bathymetric Charts used to update the GEBCO Digital Atlas includes sub annexes covering 9 sheets L Supporting Documentation for GEBCO Fifth Edition sheets used in the GEBCO Digital Atlas includes sub annexes covering 15 sheets AGS TTOMmMOO DS Page 7 of 141 CENTENARY EDITION OF THE GEBCO DIGITAL ATLAS 1 0 INTRODUCTION The First Edition of the General Bathymetric Chart of the Oceans GEBCO issued in 1905 established a tradition for publishing GEBCO as a series of printed sheets covering the globe at a scale of 1 10 million This approach continued through to the publication of a Fifth Edition of GEBCO by the Canadian Hydrographic Service in the years between 1978 and 1982 For information on the historical background to GEBCO and on the production of the Fifth Edition please refer to Annexes A and B In 1983 the Joint IOC IHO Guiding Committee for
52. EBCO SHEET 5 02 March 1980 1 to 10 million at the Equator International 1924 Hayford 46 40 N 090 00 E 72 00 N 180 00 E Head Department of Navigation and Oceanography St Petersburg Russia in collaboration with the British Oceanographic Data Centre as for published chart bathymetric depth in corrected metres Om 200m 500m and at 500m intervals thereafter down to 8500m In some areas the 50m and 100m contours are also included The digitized data for this chart were edgematched with that for GEBCO sheets 5 06 and 5 03 with the result that some of the contours at the sheet boundaries may be displaced slightly from their positions on the published chart As the digital data for GEBCO sheet 5 06 were supplied from a regularly updated data base and not digitized from GEBCO sheet 5 06 it proved difficult to achieve an edgematch with digital data for GEBCO sheet 5 02 most notably in the area of the Emperor Seamount Chain from 169 to 175 E 46 to 47 N Page 105 of 141 DATA SOURCES USED IN THE COMPILATION OF SHEET 5 02 CONTOURS a GEBCO 1 1 000 000 COLLECTED SOUNDINGS SHEETS Japan 1408N 1409N 1410N 1411N 1508N 1509N 1510N 1511N 1609N 1610N 1612N 1708N 1709N 1710N 1711N 1712N 1808N 1810N 1811N 1812N 1813N USA 1909N 1910N 1911N 1912N 1913N 2009N 2010N 2011N 2109N 2110N 2111N 2209N 2210N 2211N 2309N Data obtained by research vessels of Institute of Oceanology Academy of Scien
53. ET 5 08 January 1982 1 to 10 million at the Equator International 1924 Hayford 00 00 N 098 00 W 46 40 N 010 00 E The area from 90 to 98 W is only covered between 18 and 30 N while the area from 0 to 10 E is only covered between 0 and 7 N Bureau Gravimetrique International Toulouse France in collaboration with Institut Geographique National Paris France and the British Oceanographic Data Centre as for published chart except for the area 70 W to 10 E 0 to 7 N which is covered in the digital data for GEBCO sheet 5 12 The digital data for the area south of Central America i e the area south of a line joining the points 16 N 90 W 8 30 N 82 W 9 15 N 79 W 8 16 N 77 W is also omitted and is covered in GEBCO sheet 5 07 Page 18 of 141 Contour Units bathymetric depth in corrected metres Contours Present Om 200m 500m and at 500m intervals thereafter down to 8000m However for areas away from the Mid Atlantic Ridge intermediate contours are also included and the digital data set will be found to include contours at the following depths 50m 100m and at 100m intervals thereafter down to 6000m DATA SOURCES USED IN THE COMPILATION OF SHEET 5 08 CONTOURS SOUNDINGS ADDITIONAL TO GEBCO 1 1 000 000 COLLECTED SOUNDINGS SHEETS B J Collette unpublished soundings B C Heezen and M Tharp working sheets 4 inches per degree for GEBCO chart 5 12 O N to 7 N RRS Discovery cruise
54. F J 1977 Marine Seismic Measurements in the New Zealand Region New Zealand Journal of Geology and Geophysics 20 719 777 Deighton l Falvey D A and Taylor D J 1976 Depositional Environments and Geotectonic Framework Southern Australian Continental Margin Australian Petroleum Exploration Association Journal 25 36 Halunen Jr A J 1979 Tectonic History of the Fiji Plateau Unpublished Ph D Thesis University of Hawaii Hayes D E and Conolly J R 1972 Morphology of the Southeast Indian Ocean In D E Hayes Editor Antarctic Oceanology II The Australian New Zealand Sector Antarctic Research Series Volume 19 American Geophysical Union 125 146 Hayes D E Frakes L A et al 1975 Initial Reports of the Deep Sea Drilling Project Volume 28 1017 pp Hayes D E and Talwani M 1972 Geophysical Investigations of the Macquarie Ridge Complex In Hayes D E ed Antarctic Oceanology II The Australian New Zealand Sector 19 American Geophysical Union p 211 234 Heezen B C Tharp M and Bentley C 1972 Morphology of the Earth in Antarctic and Sub Antarctic In Antarctic Map Folio Series 15 American Geographical Society 16 pp 8 pl Karig D E and Mammerickx J 1972 Tectonic Framework of the New Hebrides Island Arc Mar Geol 12 187 205 Kennett J P 1977 Cenozoic Evolution of Antarctic Glaciation The Circum Antarctic Oceans and their Impact on Global Paleoceanography Journal of Geophysical
55. However the updated Version 3 0 coastline was supplied directly to BODC by the British Antarctic Survey The coastline was converted at BODC into labelled vector streams of paired latitude and longitude values stored in the same format as used in GEBCO for depth contours The only difference is that the depth value is replaced by a numeric feature code in the range 22010 to 22100 that represents the type of coastline as coded in the ADD Page 40 of 141 ADD GEBCO Type of coastline code code 22010 1 Ice coastline definite 22011 1 Rock coastline definite 22012 1 Grounding line definite 22013 1 Rock against ice shelf definite 22020 1 Ice coastline approximate 22021 1 Rock coastline approximate 22022 1 Grounding line approximate 22023 1 Rock against ice shelf approximate 22030 2 Iceberg tongue 22040 2 Floating glacier tongue 22050 2 Ice shelf front 22090 1 Ice rumples distinct 22100 1 Ice rumples indistinct The coding of some features is subdivided into definite and approximate so as to flag those features whose definition is uncertain either through the lack of good quality imagery or detailed maps more specifically it reflects the inherent difficulty of interpreting the grounding line from satellite images Although the full ADD code is maintained in the GEBCO Digital Atlas a simplified GEBCO version is also available coded as follows 1 Landward limit of seawater 2 Seaw
56. Land Antarctica Nature 269 686 687 Page 137 of 141 Bergh H W and Norton 1 0 1976 Prince Edward Fracture Zone and the evolution of the Mozambique Basin J Geophys Res 81 5221 5239 Bruhn R L and Dalziel W D 1977 Destruction of the Early Cretaceous marginal basin in the Andes of Tierra del Fuego Talwani M and Pitman W C Ill Eds Back Arc Basins Maurice Ewing Series 1 Amer Geophys Union Washington D C 395 405 Dalziel W D 1974 Evolution of the margins of the Scotia Sea Burk C A and Drake C L Eds The Geology of Continental margins New York Springer Verlag New York Inc 567 579 Dalziel W D and Elliot D H 1973 The Scotia Arc and Antarctic margin Nairn A E M and Stehli F G Eds The ocean basins and margins The South Atlantic Plenum Press New York 171 245 Dalziel W D de Wit M J and Palmer K F 1974 A fossil marginal basin in the Southern Andes Nature 250 291 294 de Wit M J 1977 The evolution of the Scotia Arc as a key to the reconstruction of southwestern Gondwanaland Tectonophysics 37 53 81 du Plessis A 1977 Sea floor spreading south of the Agulhas Fracture Zone Nature 270 719 721 du Plessis A and Simpson E S W 1974 Magnetic anomalies associated with the southeastern continental margin of South Africa Marine Geophys Res 2 99 110 Emery K O Uchupi E Bowen C O Philips J and Simpson E S W 1974 Continental ma
57. N 24 00 W to 36 00 W 4 Robin Falconer and Jane Handley Interpolation of contours at 500 metre intervals for 03 00 S to 40 00 S 70 00 W to 20 00 E 5 The bathymetric contours for 00 00 N to 07 00 N 10 00 E to 40 00 W not covered by any of the above were taken from GEBCO sheet 5 08 6 Additional contours were compiled by Peter Hunter Page 129 of 141 DATA SOURCES USED IN THE COMPILATION OF SHEET 5 12 CONTOURS BATHYMETRY BETWEEN 03 00 S AND 40 00 S BASED ON Cherkis N Z Fleming H S amp Brozena J M 1989 Bathymetry of the South Atlantic Ocean 03 00 S to 40 00 S Map and Chart Series MCH 069 The Geological Society of America Boulder Colorado USA DETAILED SURVEYS AND COMPILATIONS 1 Damuth J E Flood R D Kowsmann R O Belderson R H and Gorini M A 1988 Anatomy and growth pattern of Amazon deep sea fan as revealed by long range side scan sonar GLORIA and high resolution seismic studies American Association of Petroleum Geologists Bulletin 72 8 885 911 2 Udintsev G B 1988 R V Akademik Nikolai Strakhov cruises 7 1988 11 1990 and 12 1991 Equaridge Programme Multi beam surveys Russian Academy of Sciences Moscow 3 Martin L 1970 Institute of Geological Sciences London Report No 70 16 105 119 and Martin L 1977 Travaux et Documents de l O R S T O M No 61 Paris 265 pp 4 Thomas M V 1989 A Geophysical Study of the Romanche Transform and Surrounding Ar
58. N meeting at which the name was approved and the nature of the supporting evidence and a brief history of the origin of the name Information may also be given on any variations or changes in the name or any differences with the name adopted for the feature by the Advisory Committee on Undersea Features of the U S Board on Geographic Names ACUF BGN Please note that on occasion named features will appear when there is no obvious indication of the feature in the GDA bathymetry In general this implies that the echo sounding data used to identify the feature was not available when the GEBCO contours in the area were compiled Users wishing to obtain a full copy of the IHO IOC Gazetteer of Geographical Names of Undersea Features are directed to the GEBCO website at www ngdc noaa gov mgg gebco where it is available in the form of a spreadsheet Oceanic and Antarctic Islands A geographically referenced list of about 400 oceanic islands was specially prepared by BODC to complement the GDA The list is not intended to be comprehensive in any way nor are the names given to the individual islands intended to be definitive The list focuses primarily on small islands in the open ocean and excludes islands in the Mediterranean the Gulf of Mexico the Caribbean Sea except for the Windward and Leeward Islands and the inner seas of South East Asia It also excludes islands on the continental shelves in close proximity to land and all continental
59. O charts echo soundings are normally corrected for regional variations in the velocity of sound in seawater by the use of Carter s Tables NP132 Echo Sounding Correction Tables 3rd Edition D J T Carter Page 89 of 141 Hydrographic Department Taunton 1980 However for GEBCO Sheet G 07 such corrections were not made as there is considerable uncertainty on the accuracy of Carter s Tables in the area of the Weddell Sea and the sound velocity was assumed to be 1500m s throughout the water column By way of comparison it may be noted that for the Weddell Sea area the corrections from Carter s Tables are as follows Contourdepth m 200 500 1000 1500 2000 2500 3000 Correction m 8 18 29 39 47 53 55 Contour depth m 3500 4000 4500 5000 5500 6000 Correction m 54 51 45 36 24 8 PREPARATION OF GEBCO SHEET G 07 This data set was compiled in two parts Area A 65 79 S 66 0 W which was submitted by AWI to BODC in 1997 and Area B 60 66 S 75 15 W which was submitted by AWI in 2001 Area B updates the bathymetry of Area A in the overlapping area between 65 66 S In 2001 AWI also provided BODC with updated bathymetry for the area from 2 W to 2 E PREPARATION OF AREA A Authors Hans Werner Schenke Heinrich Hinze Fred Niederjasper Tilo Schone Bernd Hoppmann and Semme Dijkstra Alfred Wegener Institute for Polar and Marine Research AWI Bremerhaven Germany Until the AWI started its scientific activ
60. Oceanographic Data Centre BODC at the Proudman Oceanographic Laboratory Birkenhead UK a total of some 250 pairs of sheets The contours and tracklines were digitised by Pauline Weatherall at BODC employing raster scanning techniques and subsequent vectorisation and labelling using Laser Scan s VTRAK system Careful control was exercised in the geographic registration of the material which was checked at one degree intervals of both latitude and longitude across the full area of each sheet Both contours and tracklines were digitised with a registration accuracy within the line thickness of the source material For the area between 10 W and 20 E the contours were hand digitised by Karen Walters and Jon Anderson at SIO and the files transmitted to BODC for quality control Miss Weatherall was responsible for edgematching the digitised contours across sheet boundaries so as to provide a seamless data set She was also responsible for incorporating a digital coastline into the data set using the Defense Mapping Agency s World Vector Shoreline north of Page 96 of 141 60 S and the Scientific Committee on Antarctic Research s coastline of Antarctica south of 60 S Careful checks were made to ensure that the bathymetric contours were consistent with the coastlines particularly around islands The contouring and digitizing work was undertaken over a period of more than 10 years as new sounding data continued to be acquired over this period
61. Oceans CNEXO Brest France R R S Discovery Cruise 144 1984 Unpublished GLORIA sidescan sonar images Institute of Oceanographic Sciences Wormley U K R R S Discovery Cruise 161 1986 Unpublished GLORIA sidescan sonar images Institute of Oceanographic Sciences Wormley U K Vanney J R and Mougenot D 1981 La Plate forme Continentale du Portugal et les Provinces Ajacentes Analyses Geomorphologique Memorias dos Servicos Geologicos de Portugal Lisboa No 28 86 pp and 41 figures Western Approaches to the Strait of Gibraltar Submarine Topography Scale 1 1 000 000 1969 Admiralty chart C6101 Hydrographer of the Navy Taunton U K Page 77 of 141 Author Note Sheet Limits Scale Horizontal Datum Contour Units Contours present Coastline Source ANNEX K 5 GEBCO Sheet G 05 Mid Atlantic Ridge to NW Africa Compiled for GEBCO 2002 by Peter M Hunter Southampton Oceanography Centre United Kingdom East of the 4600m contour off the coast of NW Africa the bathymetry is taken from sheet 1 06 of the International Bathymetric Chart of the Central Eastern Atlantic IBCEA compiled by the Service Hydrographique et Oceanographique de la Marine SHOM France 18 N 35 N 47 W 14 W see below for detailed coverage Contours compiled and digitized at a range of scales from 1 250 000 to 1 1 250 000 million WGS 84 Bathymetric depth in corrected metres The area of the sheet from
62. RS Discovery Contours and tracklines were digitised directly from these charts for incorporation into GEBCO Sheet 97 3 The area comprises four major sub areas SUB AREA A Porcupine Seabight and Porcupine Bank North of 49 30 N Compiled by P M Hunter IOS and N H Kenyon IOS in 1984 using a original echo sounding chart records from all IOS cruises crossing the region since 1966 In addition to depths the positions of breaks of slope canyon axes ridge crests and other features were extracted from the records b NC Marcel Bayard survey for the CANTAT II telephone cable M T Jones IOS c Seabeam data covering the Goban Spur the outer edge of the Porcupine Bank and the Gollum Channel system in the Seabight collected during the Norestlante 1 cruise of NO Jean Charcot in 1983 J C Sibuet COB d GLORIA records from RRS Discovery cruise 83 covering the channel system in the Seabight northern edge of Goban Spur and southern edge of Porcupine Bank e East west sounding tracks at spacing of 10km taken by USNS Sgt Curtis F Shoup north of 51 N US Naval Oceanographic Office SUB AREA B Goban Spur 48 49 30 N 11 14 W Compiled by P M Hunter IOS and J C Sibuet COB in 1983 Based on Seabeam coverage over about two thirds of the area by NO Jean Charcot and complemented by GLORIA images parallel to the shelf break Conventional single beam soundings were used to fill in gaps in Seabeam coverage Reference Sibuet
63. Research 82 3843 3860 Mammerickx J Chase T E Smith S M and Taylor I L 1971 Bathymetry of the South Pacific Charts 11 13 1 4 300 000 Scripps Institution of Oceanography Molnar P Atwater T Mammerickx J and Smith S M 1977 Magnetic Anomalies Bathymetry and the Tectonic Evolution of the South Pacific Since the Late Cretaceous Geophysical Journal Royal Astronomical Society 40 383 420 Page 125 of 141 Packham G H and Terrill A 1975 Submarine Geology of the South Fiji Basin Pp 617 45 in Initial Reports of the Deep Sea Drilling Project Leg 30 National Science Foundation University of California La Jolla Terrill A and Packham G H 1974 Bathymetry of the South Fiji Basin 1 1 700 000 Department of Geology and Geophysics University of Sydney Australia Weissel J K and Hayes D E 1977 Evolution of the Tasman Sea reappraised Earth and Planetary Science Letters 36 77 84 Weissel J K Hayes D E and Herron E M 1977 Plate Tectonic Synthesis the Displacements Between Australia New Zealand and Antarctica Since the Late Cretaceous Marine Geology 25 231 277 Page 126 of 141 ANNEX L 11 GEBCO Sheet 5 11 GEBCO sheet 5 11 was published in March 1980 by the Canadian Hydrographic Service under the authority of the IHO and IOC Scientific Coordinators Cartography by Published Chart Projection Ellipsoid Southern Limit Western Limit Northern Limit Eastern Limit
64. Survey and NOAA National Ocean Survey Washington D C Chase T E Normark W R and Wilde P 1975 Oceanographic data of the Monterey Deep Sea Fan IMR Tech Rept Series TR 58 University of California San Diego California Chase T E Menard H W and Mammerickx J 1968 1969 Bathymetry of the North Pacific sheets 3 4 8 9 and 10 Scripps Institution of Oceanography and the Institute of Marine Resources University of California San Diego California Heezen B and Tharp M 1978 Bathymetric and nodule assessment map northeast equatorial Pacific Ocean 15 sheets US Geological Survey Juan de Fuca Plate Map 1978 Pacific Geoscience Center Dept Energy Mines and Resources Ottawa Canada Lonsdale P 1977 Regional shape and tectonics of the equatorial East Pacific Rise Mar Geophys Res 3 195 315 Lonsdale P 1977 and Klitgord K D 1978 Structure and tectonic history of the Eastern Panama Basin Geol Soc Am Bull 89 981 999 Morton W T and Lowrie A 1978 Regional geological maps of the Northeast Pacific Naval Oceanographic Office NSTL Station Bay St Louis Mississippi Page 16 of 141 Rosendahl B R and Dorman L M Summary of the geology and geophysics of the East Pacific Rise in the vicinity of the Siqueiros Fracture Zone in Rosendahl B R R Hekinian et al in press Initial Reports of the Deep Sea Drilling Project vol 54 Washington US Government Printing Office p 23 36 Wil
65. TIC IBCEA IBCEA Sheets 1 08 1 09 1 10 1 11 and 1 12 published by the Service Hydrographique et Oceanographique de la Marine SHOM Paris over the period 1999 to 2001 Author Editorial Board Sheet Limits Scale Horizontal Datum Contour Units Contours present Coastline Source Digitisation Note Bathymetry compiled by SHOM under the guidance of the IOC Editorial Board for IBCEA Andre Roubertou Chairman France Isabelle Niang diop Vice Chairman Senegal Gilles Bessaro Michel Le Gouic France Boubacar Diallo Guinee Michel Huet IHB Laurence Awosika Nigeria Jose Manuel Fialho Lourenco Portugal Vladim Sobolev Russia Director Instituto Hidrografico de la Marina Spain Mensah Koffi Nutsudza Togo E John W Jones U K Troy Holcombe U S A in collaboration with Olivier Vicaire doctor of geophysics France Composite from IBCEA 1 08 5 11 N 12 18 N 21 47 W 11 17 W May 1999 IBCEA 1 09 0 31 S 6 40 N 20 30 W 10 00 W October 2000 IBCEA 1 10 0 31 S 6 40 N 10 00 W 0 30 E October 2000 IBCEA 1 11 0 31 S 6 40 N 0 30 E 11 00 E March 2001 IBCEA 1 12 7 42 S 0 31 S 3 10 E 13 40 E March 2001 publication dates of printed charts Contours compiled and digitized at a scale of 1 250 000 Printed charts published on Mercator projection at 1 1 million at 20 N WGS84 Bathymetric
66. This area is covered by the digital data in GEBCO sheet 5 12 bathymetric depth in corrected metres 0 200 500 1000m and at 500m intervals thereafter down to 8000m plus the following i 20 40 60 80 and 100m on the continental shelf east of Argentina ii 750 1250 and 1750m on the Falkland Plateau and off the Continental Shelf east of Argentina iii 3600 3700 3800 3900 and 4100m west of Chile and north of 48 S iv at 250m intervals from 250m to 4750m for the chart area south of 64 S and east of 55 W Page 136 of 141 Comments On the published chart there is an erroneous chain of seamounts in the area 65 5 to 67 S 22 5 to 25 5 W sometimes referred to as the Islas Orcadas seamounts These have been found to be non existent and their contours have been removed from the digitized data set DATA SOURCES USED IN THE COMPILATION OF SHEET 5 16 CONTOURS Lamont Doherty Geological Observatory Columbia Univ Palisades New York 10964 USA Woods Hole Oceanographic Institution Woods Hole Massachusetts 02543 USA Scripps Institution of Oceanography La Jolla California 92093 USA Defense Mapping Agency Sutland Maryland USA National Geophysical and Solar Terrestrial Data Centre Boulder Colorado 80302 USA University of Cape Town Rondebosch 7700 Cape Town South Africa Instituto Hidrografico de la Armada Casilla 324 Valparaiso Chile Servicio de Hidrografia Naval Avenida Montes de Oca 2124 1271 Buenos
67. UK in collaboration with the British Oceanographic Data Centre as for published chart except for the bathymetric contours in the western part of Hudson Bay from the area 90 to 95 W 55 to 65 N This area is covered in the digital data for GEBCO sheet 5 04 bathymetric depth in corrected metres Om 200m 500m and at 500m intervals thereafter down to 6000m with two additional contours at 7000m However for many areas intermediate contours are also included and the digital data set will be found to include contours at the following depths 50m 100m 300m 400m and at 200m intervals thereafter down to 6000m with an additional contour at 4900m The digitized data for this chart were edgematched with that for GEBCO sheets 5 02 and 5 07 with the result that some of the contours at the sheet boundaries may be displaced slightly from their positions on the published chart Page 107 of 141 DATA SOURCES USED IN THE COMPILATION OF SHEET 5 03 CONTOURS SCIENTIFIC LITERATURE Anonymous Bathymetric base maps The US Naval Oceanographic Office and Defense Mapping Agency Hydrographic Center Anonymous 1971a Bathymetric atlas of the northeastern Pacific Ocean Prepared by Scripps Institution of Oceanography under the direction of T E Chase and H W Menard H O Pub No 1303 US Naval Oceanog Office Anonymous 1971b Bathymetric atlas of the northcentral Pacific Ocean Prepared by Scripps Institution of Oceanography under the dire
68. UK The tracklines were not available on the original chart Reference Johnson G L amp Vogt P R 1973 Mid Atlantic Ridge from 47 to 51 North Geological Society of America Bulletin 84 p 3443 3462 Page 62 of 141 AREA 97 3 08 ACTIVE PART OF CHARLIE GIBBS FRACTURE ZONE Digitised from unpublished 1 250 000 scale bathymetric chart compiled by the Institute of Oceanographic Sciences Wormley UK in 1978 Bathymetric interpretation relies heavily on a side scan sonar survey RRS Discovery Cruise 84 June July 1977 using the long range 30km double sided sonar of GLORIA Mk II and a hull mounted medium range 2 5km sonar The sonar coverage was not completely overlapping Chart compiled at a contour interval of 100m corrected using RRS Discovery cruise 84 echo soundings in conjunction with soundings from HMS Hecate UK Admiralty USNS Gibbs US Naval Research Laboratory Washington NO Jean Charcot Centre Oceanologique de Bretagne Brest and RV Cirolana Fisheries Laboratory Lowestoft Ship tracks were adjusted within the limits of the navigation systems used Loran C and transit satellites to bring soundings in line with the physiographic features seen on the GLORIA records Reference Searle R C 1981 The active part of Charlie Gibbs Fracture Zone a study using sonar and other geophysical techniques Journal of Geophysical Research 86 p 243 262 AREA 97 3 09 ROCKALL BANK Interpolated from Admiralty Chart C6091 publis
69. Wiesbaden in April 1903 under the chairmanship of Prince Albert and gratefully accepted the Prince s offer to organise and finance the production of a new series to be designated The General Bathymetric Chart of the Oceans GEBCO The series on a scale of 1 10 million was to be composed of 16 sheets on Mercator projection together with 8 sheets on gnomonic projection covering the polar regions Work on the First Edition of GEBCO began in June 1903 with a team of seven draughtsmen under the direction of Lieutenant Ch Sauerwein Extremely rapid progress was made and the series was completed in a period of 7 months The lithographed charts were presented to the Paris Academy of Sciences in January 1904 and later in the year to the Eighth International Geographical Congress in Washington D C In making the presentation Professor Thoulet remarked Here then is everything that is known about the relief of the ocean floor For many years to come mariners telegraphists engineers oceanographers and scientists will continue their soundings for now we must proceed to fill in the details no point of any sea on the globe will escape our investigations The First Edition contained over 18 000 soundings selected mainly from British Admiralty Charts with additional data incorporated from soundings obtained by cable laying vessels Depth contours were shown at 200m 500m 1000m and at 1000m intervals thereafter Second Edition At the opening
70. XICO IBCCA The bathymetry of this sheet is taken from sheets 1 01 to 1 09 of the International Bathymetric Chart of the Caribbean Sea and the Gulf of Mexico IBCCA compiled under the guidance of the IOC Editorial Board for IBCCA Chief Editor Mario Alberto Reyes Ibarra INEGI Bathymetry for these IBCCA sheets was completed in the period 1997 to 2001 while the data sets were submitted to BODC in 2002 Authors Scientific Coordinators Sheet Limits IBCCA Sheets 1 01 to 1 04 and 1 09 compiled by the US National Geophysical Data Center NGDC Troy L Holcombe IBCCA Sheets 1 05 and 1 06 compiled by Instituto Nacional de Estadistica Geografia e Informatica INEGI Mexico Jose Luis Frias Salazar IBCCA Sheets 1 07 and 1 08 compiled by Agencia de Cartografia Nautica Cuba Rolando Feito Sarduy 15 N to 33 N 101 W to 69 W and to 61 W from 15 N to 24 N Limits of individual IBCCA Sheets Scale Horizontal Datum Contour Units Contours present Coastline Source 24 33 N 101 93 W 1 01 93 85 W 1 02 85 77 W 1 03 77 69 W 1 04 15 24 N 101 93 W 1 05 93 85 W 1 06 85 77 W 1 07 77 69 W 1 08 and 69 61 W 1 09 contours compiled and digitized on Mercator sheets at a scale of 1 500 000 WGS 84 bathymetric depth in corrected metres standard contours at Om 20m 40m 60m 80m 100m 200m and at 200m intervals thereafter down to 8 400m Also included as standar
71. a Marine Paris IBCEA Sheet 1 06 Sources of detailed bathymetric surveys Institut National des Sciences de l Univers INSU Institut Francais de Recherche Scientifique pour le developpement en cooperation ORSTOM JEAN CHARCOT 1971 Institut Francais de Recherche de Exploitation de la Mer IFREMER JEAN CHARCOT 1988 SUROIT 1983 ATALANTE 1992 to 1995 Institute of Oceanographic Sciences IOS DISCOVERY 1983 Lamont Doherty Geological Observatory VEMA 1961 to 1973 CONRAD 1973 Scripps Institution of Oceanography GLOMAR CHALLENGER 1975 Texas A amp M University JOIDES RESOLUTION 1986 US Geological Survey 1971 Woods Hole Oceanographic Institute ATLANTIS II 1973 Page 80 of 141 IBCEA Sheet 1 06 Charts consulted Gravimetrie Anomalies a l air libre pour IBCEA d apres le modele Smith W H F amp Sandwell D T J G R 99 1997 SHOM Paris France 1997 1998 Topographie pour IBCEA predite a partir de donnees altrimetriques et bathymetriques Modele Smith W H F amp Sandwell D T J G R 99 1994 SHOM Paris France 1997 Hunter P M Searle R C and Laughton A S 1983 Bathymetry of the Northeast Atlantic Sheet 5 Continental Margin Off West Africa Scale 1 2 400 000 Admiralty Chart C6570 Hydrographer of the Navy Taunton U K Page 81 of 141 ANNEX K 6 GEBCO Sheet G 06 Central Eastern Atlantic INTERNATIONAL BATHYMETRIC CHART OF THE CENTRAL EASTERN ATLAN
72. a sismique reflexion et de la modelisation analogique Bull Soc geol France 163 3 207 216 Basile C Mascle J Popoff M Bouillin J P and Mascle G 1993 The Ivory Coast Ghana transform margin a marginal ridge structure deduced from seismic data Tectonophysics 222 1 19 Basile C Mascle J Sage F Lamarche G and Pontoise B 1996 3 Pre cruise and site surveys a synthesis of marine geological and geophysical data on the Cote d Ivoire Ghana transform margin In Mascle J Lohmann G P Clift P D et al Proceedings of the Ocean Drilling Programme Initial Reports Vol 159 47 60 Behrendt J C Schlee J Robb J M and Silverstein M K 1974 Structure of the Continental Margin of Liberia West Africa American Association of Petroleum Geologists Bulletin 85 1143 58 Blarez E 1986 La marge continentale de Cote d lvoire Ghana structure et evolution d une marge continentale transformante Ph D Thesis Universite Pierre et Marie Curie Paris 188 p Blarez E and Mascle J and the shipboard scientific team 1986 Les marges continentales transformantes ouest africaines Guinee Sierra Leone Cote d lvoire Ghana Campagne Equamarge janvier fevrier 1983 Campagnes Oceanographiques Francaises Publications IFREMER 3 292 p Blarez E Mascle J Affaton P Robert C Herbin J P and Mascle G 1987 Geologie de la pente continentale ivoiro ghaneenne resultats de dragages de
73. age 41 of 141 million In general the maps had been published without recourse to satellite imagery When merging the data from the different map series to create a seamless coastline reference was made to satellite images as these usually provided a clearer overview of the shape and position of coastal features The quality of the coastline was greatly enhanced through the interpretive analysis of Landsat images by Dr Charles Swithinbank at the Scott Polar Research Institute Reasonable Landsat coverage was available for most of the coastline in the form of 1 1 million scale photographic products The digitised map sheets were plotted out at 1 1 million scale on clear acetate film which was then overlaid on the satellite images Enhanced detail of the coastline and linework interpretations of features such as grounding lines and ice fronts indicated on the satellite images were transferred by hand to the film overlays using headlands and rock outcrops for position control The revised vector data were digitised directly from the acetate sheets and then compared with the original map derived versions In complicated areas where more detailed maps 1 250 000 scale were available the revised data were modified to accord with the detail shown on the original maps Much of the coastline of Dronning Maud Land between 5 E and 45 E was not covered by conventional medium scale linework maps The coastline for this sector was prepared at Cambridge by dig
74. ailed survey special study areas the origins of which are described below The digitised contours for areas 1 to 7 were already present in the data set produced for IOS Sheets 1 and 2 but without corresponding trackline control information However for areas 8 and 9 the contours were digitised from higher scale source material while the contours in areas 10 and 11 are based on updated bathymetry compiled subsequent to the publication of IOS Sheets 1 and 2 AREA 97 3 01 IRMINGER BASIN Contours extracted from bathymetric chart produced by the US Naval Oceanographic Office and the Deutsches Hydrographisches Institut Based primarily on echo soundings from cruises of USNS Lynch in summer 1972 and autumn 1973 and earlier cruises of Meteor The scale of the original chart is not documented and the trackline control information is missing Reference Johnson G L Sommerhoff G amp Egloff J 1975 Structure and morphology of the west Reykjanes basin and the southeast Greenland continental margin Marine Geology 18 3 p 175 196 Page 60 of 141 Geographic coverage of GEBCO Sheet 97 3 and location of special survey areas 64 55 50 47 AREA 97 3 02 REYKJANES RIDGE NORTH Contours interpolated from unpublished bathymetric chart compiled by G L Johnson of the US Naval Oceanographic Office in the late 1960s Original chart was on Mercator projection scaled at 2 inches per degree longitude approx 1 1 million wit
75. al Research Arlington USA Scripps Institution of Oceanography La Jolla USA Canadian Hydrographic Service Ottawa Canada Bedford Institute of Oceanography Dartmouth Canada amp New Zealand Oceanographic Institute Wellington New Zealand Lamont Doherty Geological Observatory New York USA Scripps Institution of Oceanography La Jolla USA IOS Deacon Laboratory Wormley UK Naval Research Laboratory Washington USA Lamont Doherty Geological Observatory New York USA Vernadsky Institute of Geochemistry Moscow Russia GeoResearch Associates Waikanae New Zealand Lamont Doherty Geological Observatory New York USA Bedford Institute of Oceanography Dartmouth Canada amp New Zealand Oceanographic Institute Wellington New Zealand Lamont Doherty Geological Observatory New York USA Scripps Institution of Oceanography La Jolla USA Lamont Doherty Geological Observatory New York USA Lamont Doherty Geological Observatory New York USA Office of Naval Research Arlington USA Canadian Hydrographic Service Ottawa Canada University of Oslo Norway Department of Energy Mines and Resources Ottawa Canada Office of Naval Research Arlington USA Universit Pierre et Marie Curie Paris France Page 31 of 141 Copies of the Fifth Edition sheets either flat or as a boxed set of folded sheets with supporting volume can be purchased direct from Hydrographic Chart Distribution Office PO Box 8080 Ottawa Ont
76. al bands of 360 degrees x 60 points degree 1 21 601 values The data range eastward from 180 W to 180 E i e the 180 value is repeated Thus the first band contains 21 601 repeated values for 90 N then followed by a band of 21 601 values at 89 59 N and so on at one minute latitude intervals down to 90 S Export through the GDA Software Interface Using the GDA Software Interface the entire one minute grid or a geographic subset of the grid may be exported into the user s own files either in a simple ASCII format or in the netCDF format described above In the simple ASCII option the export file has 11 header records with self describing fields and the grid points are written eastwards from the Northwest corner of the selected data area The data may be output either a as longitude latitude elevation with the option to store position in decimal degrees degrees and decimal minutes or degrees minutes and decimal seconds or b simply as elevation values only with either one data point per line or one row of data per line In the latter case the data values may be separated by commas spaces or output in a fixed width format Five Minute Grid The Five Minute Grid is a smoothed global version of the One Minute Grid and is not available for access via the GDA Software Interface It is available as a binary file in Directory GRIDFIVE on disc 2 It is stored as a one dimensional array of big endian 2 byte signed integer values
77. al level the global data base of echo sounding data is maintained in digital form at the IHO Data Centre for Digital Bathymetry DCDB which was established in June 1990 The Data Centre see Annex F is operated on behalf of the IHO by the US National Geophysical Data Center NGDC in Boulder Colorado The IHO DCDB s digital holdings of single beam echo sounding data are co held within NGDC s GEODAS database of worldwide underway geophysics data a major international database of underway bathymetry magnetics gravity and seismic shot point data From time to time the GEODAS database is published by NGDC on CD ROM complete with supporting access software As further data are acquired at NGDC they are made available to users over the Internet before then being included in the next release of the GEODAS CD ROM Incorporated within the search and retrieval facility of the package is a trackline inventory comprising a simplified navigation file for each cruise leg contributing data to the database Sufficient navigation points are included in the inventory to replicate the trackline coverage of echo sounding data lodged in the database For use within the GEBCO Digital Atlas Dan Metzger of NGDC kindly provided BODC with a copy of this trackline inventory updated to cover the data available as of 1 June 2002 The trackline inventory of echo sounding data has been reformatted at BODC into unlabelled trackline vectors in geographic coordinates in a s
78. and Setbal Canyon IFREMER France 4 Mougenot D Kidd R B et al 1984 Geological interpretation of combined SEABEAM GLORIA and seismic data from Porto and Vigo Seamounts Iberian continental margin Marine Geophysical Researches 6 329 363 5 Vanney J R and Mougenot D 1981 La plate forme continentale du Portugal et les provinces adjacentes analyse geomorphologique Memorias dos Servicos Geologicos de Portugal No 28 86 pp and 41 figs Lusitaine cruises 71 73 74 75 Hesperides cruises 76 78 6 Regnauld H 1987 Geormorphologie de la pente continentale du Portugal Publiations du Department de Geographie de l Universite de Paris Sorbonne No 15 141pp Mougenot D 1989 Geologia da margem Portuguesa Instituto Hidrografico Lisboa Documentos Tecnicos No 32 259pp 7 WVanney J R and Mougenot D 1990 A gouf type Canyon the Canhao da Nazare Portugal Oceanologica Acta 13 1 1 14 and bathymetric chart at scale 1 150 000 Page 76 of 141 8 H M S Vidal 1959 Unpublished survey UK Hydrographic Office 9 Soundings sheets maintained by IHPT Instituto Hidrografico Portugal 10 Laughton A S Roberts D G and Graves R 1975 Bathymetry of the northeast Atlantic Mid Atlantic Ridge to southwest Europe Deep Sea Research 22 791 810 and Admiralty chart C6568 scale 1 2 4 million Lallemand S Maze J P Monti S and Sibuet J C 1985 Presentation d une carte bathymetrique de l
79. and and Antarctica Ph D thesis Victoria University of Wellington New Zealand Falconer R K H and Falconer R F 1979 Seismicity fracture zones and poles of rotation of the Pacific Antarctic and Indian Antarctic plate boundaries Third Antarctic Geology and Geophysics Symp University of Wisconsin Press in press Page 139 of 141 Goodell H G Houtz R et al 1973 Marine Sediments of the Southern Ocean In Antarctic Mem Folio Series 17 American Geographic Association 18 pp 9 pl Hayes D E Frakes A et al 1975 Initial Reports of Deep Sea Drilling Project vol 28 1017 p Heezen B C Tharp M and Bentley C 1972 Morphology of the Earth in the Antarctic and Subantarctic In Antarctic Map Folio Series 16 American Geographical Society 16 pp 8 pl Hollister C D and Heezen B C 1967 The floor of the Bellingshausen Sea In J B Hersey Ed Deep Sea Photography The Johns HopkinsPress Baltimore The Johns Hopkins Oceanographic Studies 3 117 189 Hurley D E and Krause D C 1976 Hjort bathymetry New Zealand Oceanographic Institute Chart Oceanic Series 1 1 000 000 Jacobs S S Bruchhausen P M Rosselot F L Gordon A L Amos A F and Belliard M 1972 Hydrographic stations bottom photographs current measurements nephelometer profiles USNS Eltanin Reports Cruises 37 39 1969 42 46 1970 Technical Report TR 1 CU 1 71 Lamont Doherty Geological Observatory of Columbia University
80. and new names are added as and when they are approved by the Sub Committee In 1987 the parent bodies of GEBCO i e the IHO and the IOC both adopted similar motions aimed at improving the standardization of naming undersea features in an effort to curb the indiscriminate and unregulated naming of undersea features in articles submitted to professional journals or on ocean charts or maps New names were appearing without any close scrutiny being made concerning their suitability or even whether the feature had already been discovered and named The motions strongly encouraged marine scientists and other persons in Member States wishing to name undersea features to check their proposals with published Gazetteers of Undersea Feature Names taking into account the guidelines contained in the IHO IOC publication Standardization of Undersea Feature Names including the use of the Undersea Feature Name Proposal Form contained therein to submit all proposed new names for clearance either to their national authority or Page 46 of 141 where no such national authority exists to the IOC or IHB for consideration by the GEBCO Sub Committee on Geographical Names and Nomenclature of Ocean Bottom Features which may advise on any potential confusing duplication of names It is now generally understood that proposals for the naming of undersea features located in international waters should be sent directly to the IHB or the IOC The motions al
81. aphy La Jolla and represents a major personal achievement of considerable benefit to GEBCO and its user community The contours were compiled on some 250 sheets at a scale of four inches per degree longitude approximately 1 1 million over a ten year period up to 2002 The hand drawn contour sheets with accompanying trackline sheets were digitized by Pauline Weatherall at BODC In addition to the original 500 sheets contours and tracklines over 600 sections of update charts were delivered to BODC for digitizing during the project The work was completed in September 2002 G 09 Waters around New Zealand see Annex K 9 The regional bathymetric map of New Zealand was delivered as a contribution to GEBCO by lan Wright of the National Institute of Water and Atmospheric Research NIWA in Wellington The data were submitted to BODC in digital form in 2000 BODC completed its work on incorporating these data into the GEBCO Digital Atlas in October 2002 In merging the new sheets into the GDA careful attention was paid to edgematching the basic GEBCO contours i e 200m 500m and 500m intervals thereafter across the boundaries of the sheets into the surrounding GDA bathymetry so as to maintain seamless bathymetry Adjustments were made as necessary taking due account of the underlying trackline control information the adjustments were normally made from outside Page 13 of 141 the boundaries of the new sheets i e within the existing GDA bath
82. ard limit of floating permanent ice The SCAR Coastline is available at four different scales Full resolution contains data at their original scale of capture from the source material For most of the coastline the data were captured from maps at scales of 1 200 000 only two map sheets 1 250 000 1 500 000 and 1 1 million Interpretations from satellite images were used where no suitable maps of the coastline existed At reduced scales of 1 1 million 1 5 million and 1 10 million respectively Reductions were achieved by a process of simplification smoothing and removal of points In these reduced versions features coded as approximate are recoded to their definite equivalents The only codes present in the reduced versions are 22010 22011 22012 22013 22040 22050 and 22090 Note due to a coding error in the preparation of the 1 1 million coastline floating glacier tongues 22040 were inadvertently coded as ice shelf front 22050 All four versions have been extracted from the ADD for use in GEBCO and have been merged with their nearest equivalent scaled versions of the World Vector Shoreline PREPARATION OF THE SCAR COASTLINE VERSION 1 0 The base material for constructing the Antarctic coastline was prepared by digitising printed topographic maps produced by national mapping agencies and Antarctic research institutes For most of the coastline these maps were available at scales ranging from 1 200 000 to 1 1 P
83. ario K1G 3H6 CANADA Tel 1613 998 4931 Fax 1613 998 1217 The International Hydrographic Bureau 4 Quai Antoine 1er B P 445 MC 98011 Monaco Cedex PRINCIPALITY OF MONACO Tel 377 93 10 81 00 Fax 377 93 10 81 40 Ocean Mapping IOC Cumbers Mill Lane Sidlesham Chichester P020 7LX UNITED KINGDOM Tel amp Fax same line 44 1243 641 222 Ordering details and prices may be obtained from the GEBCO Website at www ngdc noaa gov mgg gebco Page 32 of 141 ANNEX C Digitization of the GEBCO Fifth Edition Digitization of the Fifth Edition proved a major task and took the best part of ten years to complete 1984 1993 As usual funding was a major problem and the provision of resources for the work was dependent on the foresight and goodwill of national agencies The successful completion of the task was dependent on the generous cooperation of two organisations in particular the French Institut G ographique National through support given to the Bureau Gravim trique International in Toulouse and the UK s Natural Environment Research Council NERC through support given to the British Oceanographic Data Centre BODC The digitization of the bathymetric contours and coastlines of the Fifth Edition was carried out on a sheet by sheet basis at four laboratories Bureau Gravim trique International Toulouse France 11 sheets NERC Unit for Thematic Information Systems Reading UK 4 sheets Head Department o
84. art series of high quality and thus gain strong support from the leaders of the world marine geoscientific community However it could not assist them with project funding and it is a measure of the high regard in which the GEBCO is held that so many eminent marine geoscientists were willing to give their time and energy to the Page 29 of 141 preparation of one or more sheets of the series and to obtain institutional or national funding for their in house work For each of the Fifth Edition sheets one or more Scientific Co ordinators were appointed who were responsible for co ordinating and compiling the best possible contour plots for the area of the sheet They were also responsible for working closely with the Scientific Co ordinators of adjacent sheets to ensure continuity at borders and on overlaps An independent review procedure was also set up through which all sheets had to pass before being cleared for publication For the Fifth Edition the world cover between 72 N and 72 S was as with earlier editions on Mercator projection at a scale of 1 10 million at the equator This required 16 sheets some of which were given overlap strips so as to ensure that prominent morphological features were shown in their entirety on one sheet and were not cut by an arbitrary geographical border For the same reason limits of sheets in the southern hemisphere were shifted by 20 to the east in order to give more satisfactory cover to the main ocea
85. asmania R V Aurora australis 1990 s sub Antarctic cruises Henk Brolsma Lee Belbin Ursula Ryan b Australian Geological Survey Organisation formerly Bureau of Mineral Resources Canberra 1 979 1995 tracks and soundings of geophysical survey ships in the Australian EEZ on Kerguelen Plateau and the Antarctic margin Chris Johnston Millard Coffin 2 SOJOURN 7 and TASMANTE cruises Neville Exon Peter Hill c Australian CSIRO Division of Oceanography Hobart Tasmania R V Franklin 1987 1998 tracks and soundings on continental margins EEZ and near Christmas Island Bernadette Heaney Data Librarian and Terry Byrne Page 97 of 141 2 2 d Geological Survey of Japan Marine Geophysics Section Marine Geology Department bathymetric data collected during JNOC Japan National Oil Corporation survey cruises off Antarctica R V Hakurei Maru 1980 1995 Takemi Ishihara JGS e Japanese JARE ANTAC and Soviet R V Ob 1957 58 research vessel soundings off Antarctica received via US National Geophysical Data Center Boulder Colorado f South Africa Hydrographic Office Tokai Cape throughout S A GEBCO Area of Responsibility 1990 1998 Sidney Osborne B D Law Tony Pharaoh 2 Laboratories and academic institutions a b c d e a Alfred Wegener Institut f r Polar und Meeresforschung Bremerhaven R V Polarstern pre 1998 soundings in the sub Antarctic between 10 W and 40 E Hans Werner Sc
86. atabase of soundings collected in the region from a variety of Page 56 of 141 sources as listed below In regions of sparse soundings these data were augmented with contour information as follows In the central Arctic Ocean data were incorporated from a newly published Russian map HDNO et al 1999 while information was extracted from an earlier NRL chart Perry et al 1986 for the area of Bering Strait Similarly contour information was taken from NRL maps Cherkis et al 1991 Matishov et al 1995 in the Barents and Kara Seas In the southern Norwegian Greenland Seas Baffin Bay and parts of the Canadian Arctic reference was made to the digital version of GEBCO sheet 5 17 Bathymetry in the Gulf of Bothnia was derived from a 2 E W by 1 N S digital grid compiled by Seifert and Kayser 1995 On the continental shelf of Siberia in the Laptev and East Siberian Seas and the Kara Sea east of 80 E soundings were extracted from a suite of navigational charts published by the Russian Head Department of Navigation and Oceanography HDNO 1989 1998 These soundings were used to manually draw contours at intervals of the order of 5m which were subsequently digitized for input to the grid Where no contour information was available in data sparse areas e g around Greenland provisional contours were prepared by the IBCAO group to facilitate the gridding process All data were imported to Intergraph s GIS system MGE Modular GIS Env
87. base map for Sheet 97 3 was taken from source material used in the production of two charts of the Northeast Atlantic compiled by geoscientists at the Institute of Oceanographic Sciences Wormley Surrey and published by the UK Hydrographic Office Taunton Admiralty Chart C6566 Bathymetry of the northeast Atlantic Sheet 1 Reykjanes Ridge and Rockall Plateau by A S Laughton D G Roberts amp P M Hunter published in February 1982 and covering the area 47 to 64 N 13 to 37 W Hereafter referred to as IOS Sheet 1 Admiralty Chart C6567 Bathymetry of the northeast Atlantic Sheet 2 Continental Margin around the British Isles by D G Roberts P M Hunter amp A S Laughton published in February 1977 and covering the area 47 to 64 N 6 E to 18 W Hereafter referred to as IOS Sheet 2 Page 59 of 141 Both charts were published on Mercator projection at a scale of 1 2 4 million at 41 N A discussion on the morphology of the area covered by the second sheet may be found in Roberts D G Hunter P M amp Laughton A S 1979 Deep Sea Research 26A p 417 428 The contours for these charts were compiled by hand on 1 1 million scale compilation sheets using the GEBCO Collected Oceanic Soundings Sheets maintained by the UK Hydrographic Office and the Deutsches Hydrographisches Institut as the principal source of soundings Additional sources included the GEBCO collection of the Service Hydrographique et Oceanographique
88. better NIMA World Vector Shoreline north of 60 S Scale of 1 1 million Geographic Coverage a SE Atlantic from 24 S to 72 S 12 W to 20 E with an extension to 20 W between 56 S to 60 S South of 65 S and west of 2 E the bathymetry is provided by GEBCO sheet G 07 and the two sheets are merged at this boundary b Indian Ocean from 20 E to 147 E from Asia down to Antarctica including the Gulf of Aden The north east boundary with the South China and Eastern Archipelagic Seas is along a line taken between 9 N 99 E 0 N 105 E 0 N 115 E 4 N 115 E 4 N 136 E and then southwards to the coast of Australia c SW Pacific from 24 S to 72 S 147 E to 170 E but restricted in the northeast where it abuts and is merged with GEBCO sheet G 09 in this region the eastern limit is as follows 24 31 S 158 6 E 31 47 S 157 E 47 54 S 165 E 54 57 5 S 163 5 E PREPARATION OF GEBCO SHEET G 08 The compilation and hand contouring of all echo sounding data used in the construction of Sheet G 08 was carried out by Dr Robert L Fisher of the Scripps Institution of Page 95 of 141 Oceanography SIO as part of the International Indian Ocean Data Compilation Project IODCP a collaborative venture between scientists at SIO and L Ecole et Observatoire de Physique du Globe Strasbourg France The project s aim is to produce a detailed tectonic chart for the entire Indian Ocean and the contiguous Southern Ocean
89. ble in many areas Although certain areas of the deep sea may be of sufficient commercial military or scientific importance to be examined closely by saturated surveys for the greater part of the deep oceans bathymetric charts can only be compiled from random track data of variable quality The interpretation of such data relies on the expert understanding of marine geologists and geophysicists of the processes shaping the ocean floor A major problem facing the preparation of the Fifth Edition was the chronic lack of finance available for GEBCO and the recognition that sales clearly could not begin to cover production costs at least until the complete world cover was available and the series had been given wide publicity The breakthrough came when with remarkable foresight the Canadian Government agreed to scribe print and provide sales outlets initially for the first 4 sheets of the series but later for the full 18 sheets This agreement was honoured by the Canadian Hydrographic Service which over the period 1975 to 1982 was responsible for bringing to publication the complete series of 18 Fifth Edition charts Indeed at the completion of the project the CHS also published a World Sheet with global coverage at a scale of 1 35 million With this agreement in hand the Guiding Committee was able to offer marine geoscientists in many countries of the world the possibility of publishing their work with full acknowledgements in a prestigious ch
90. boriously by a very small number of ships that could spare the time to stop on station for lengthy periods of time for the sole purpose of obtaining one spot ocean depth As a result the few deep ocean soundings obtained each year could be published in the form of lists by certain national Hydrographic Offices the major sources of data were the Lists of Oceanic Depths published regularly by the British Admiralty since 1888 the French Annales Hydrographiques and the German Annalen der Hydrographie However with the advent of the echo sounder this approach soon became impractical Third Edition There was a major change in organisation for the production of the Third Edition of GEBCO Following the death of Prince Albert his scientific team was disbanded and the Government of Monaco invited the International Hydrographic Bureau now the International Hydrographic Organization to take over the project In 1929 the Bureau was entrusted with the task of keeping the series up to date and of collating all data outside the continental shelf Data for the Third Edition were compiled by the IHB staff and hydrographic offices of the IHO Member States were requested to supply all available oceanic soundings These took the form of lists of depths together with the exact geographical position and details of sounding apparatus sea temperatures velocity of sound in seawater etc To collate the soundings the IHB established a series of 1001 plo
91. c Sciences Wormley U K 15 Black M et al 1964 Q J Geol Soc Lond 120 477 517 16 R R S Discovery II 1960 Unpublished survey Institute of Oceanographic Sciences Wormley U K 17 Laughton A S Berggren W A et al 1972 Initial Reports of the Deep Sea Drilling Project 12 Washington D C p 755 18 Berthois L and Brenot R 1966 Cartes bathymetriques du talus du plateau continental editees par L Bertois avec le concours du CNRS Inst Sci et Tech des Peches Marit Subsequent modifications by Instituit Francais du Petrole 19 Phillips J D and Fleming H S 1978 GSA MC 19 Geol Soc Amer Boulder Colorado 20 Fox P J Schroeder F W Moody R H Pitman Ill W C and Hoose P J 1978 The Bathymetry of the Oceanographer Fracture Zone and Mid Atlantic Ridge at 35 N with implications for central North Atlantic plate motion Unpublished manuscript 21 Litvin V M Marova N A Rudenko M V and Udintsev G B 1972 Oceanology 12 527 534 22 Rona P A and Gray D F 1980 Geol Soc Amer Bull 91 485 494 Also McGregor B A and Rona P A 1975 J Geophys Res 80 3307 3314 and Rona P A Harbison R N Bassinger B G Scott R B and Nalwalk A J 1976 Geol Soc Amer Bull 87 661 674 23 Van Andel H Tj and Bowen C O 1968 J Geophys Res 73 1279 1298 24 Collette B J 1980 unpublished soundings contoured by Searle R C Also Collette B J Slootw
92. ces USSR b BATHYMETRIC MAPS Scholl D Tau Rho Alpha Marlow M S Buffington E G 1974 Base map of the Aleutian Bering Sea region scale 1 2 500 000 Nichols H and Perry R B 1966 Bathymetry of the Aleutian Arc Alaska US Dept of Commerce Environmental Science Services Admin Coast and Geodetic Survey Mon 3 Plate 1 and 2 scale 1 400 000 Heezen B C and Tharp M 1975 Map of the Arctic Region American Geographical Society New York scale 1 5 000 000 at 71 N Page 106 of 141 ANNEX L 3 GEBCO Sheet 5 03 MINOR UPDATE NOTE The bathymetry in the area of GEBCO sheet 5 03 north of 64 N has been replaced by the bathymetry contained in GEBCO sheet G 01 GEBCO sheet 5 03 was published in March 1979 by the Canadian Hydrographic Service under the authority of the IHO and IOC Scientific Coordinators Cartography by Published Chart Projection Mercator Scale Ellipsoid Southern Limit Western Limit Northern Limit Eastern Limit Digitized by Geographic Area Digitized Contour Units Contours Present Comments G Leonard Johnson Office of Naval Research Arlington USA and David Monahan Canadian Hydrographic Service Ottawa Canada Geoscience Mapping Unit Canadian Hydrographic Service GEBCO SHEET 5 03 March 1979 1 to 10 million at the Equator International 1924 Hayford 46 40 N 180 00 W 72 00 N 090 00 W NERC Unit for Thematic Information Systems Reading
93. cho sounding correction can be displayed at the current cursor position A multi point distance measuring option is available between user specified points on the map display with distance presented in miles nautical miles and kilometres Supporting documentation for the source charts contributing to the displayed map can be displayed or listed out on demand 5 0 EXPORTING DATA FROM THE CENTENARY EDITION 5 1 Accessing the GEBCO One Minute Grid The GEBCO One Minute Grid is stored in Directory GRID on disc 1 as one global GMT compatible netCDF data file which may be accessed either directly by the user or through the GDA Software Interface Using the GDA Software Interface the entire one minute grid or a geographic subset of the grid may be exported into the user s own files either in a simple ASCII format or in the netCDF format Details concerning the formatting of gridded data may be found in Table 1 5 2 Exporting vector data using the GDA Software Interface All the vector data sets contained in the Centenary Edition can be exported into the user s own files through the GDA Software Interface Through this interface the user can define precisely their geographic area of interest irrespective of sheet boundaries The user can also specify which contour levels are to be selected and trackline vectors tracklines survey box outlines and sounding points can be merged in the same file as the bathymetric contours and coastlines Furth
94. ck spacing for depths from 200 to 900 meters 3 2 km track spacing for depths from 900 to 2750 meters 8 0 km track spacing for depths over 2750 meters Page 67 of 141 Digital contours from the U S Geological Survey CONMAP data base derived from U S Coast Survey 1 250 000 scale bathymetric maps were used in some areas to fill in small data gaps 2 Contours digitally generated from multibeam surveys conducted by the U S Coast Survey ships WHITING and MOUNT MITCHELL from 1988 to 1992 3 Contours provided by William R Bryant of Texas A amp M University from industry surveys compiled at a scale of 1 192 000 Track spacing from 0 45 to 0 9 km 4 Multibeam data collected by R V Gyre IBCCA SHEET 1 02 Scientific Coordinator Troy L Holcombe MGG NGDC Compiler Lisa A Taylor MGG NGDC Digital soundings from the U S National Geophysical Data Center Global Trackline Geophysical Data Base GEODAS Collecting institutions include the Institute for Geophysics University of Texas Lamont Doherty Earth Observatory of Columbia University U S Coast Survey and the U S Geological Survey Sources of detailed surveys and bathymetric contours 1 Soundings from surveys conducted by the U S National Oceanic and Atmospheric Administration National Ocean Service Coast Survey Track spacing varies with depth 0 1 to 0 8 km track spacing for depths from 0 to 200 meters 0 8 to 1 6 km track spacing for depths from 200 to 900 meters 3
95. clusion in GEBCO Sheet 97 3 Reference Fleischer U Holzkamm F Vollbrecht K amp Voppel D 1974 Die Struckur des Island Faroer Ruckens aus geophysikalischen Messungen Deutsche Hydrographische Zeitschrift 27 2 p 97 113 AREA 97 3 06 ROSEMARY BANK Based on unpublished survey of Rosemary Bank by HMS Hecate in 1967 UK Hydrographic Office consisting of east west tracks at a spacing of 4 6km but with a spacing of 2 3km over the Bank and 1 2km over the crest of the Bank Survey sheet was compiled on Mercator projection at a scale of 1 200 000 with soundings plotted out in fathoms uncorrected Sheet was contoured at intervals of 100m corrected and transcribed onto 1 1 million compilation sheets maintained at the Institute of Oceanographic Sciences Wormley UK Tracklines digitised from original survey sheet AREA 97 3 07 MID ATLANTIC RIDGE 47 to 51 N Interpolated from unpublished fair drawn bathymetric chart on Mercator projection scaled at 1 25 inches per degree longitude approx 1 2 million and with a contour interval of 100 fathoms uncorrected Chart produced by the US Naval Oceanographic Office based on a comprehensive echo sounding survey in the late 1960s consisting of a series of east west tracks spaced less than 10km apart throughout the area The chart was recontoured at intervals of 100m corrected and transcribed onto 1 1 million compilation sheets maintained at the Institute of Oceanographic Sciences Wormley
96. consistent with the morphology of the region in sparsely sounded areas the compilation was supplemented with contours taken from IOS Sheet 1 which was assumed to be based on older and less accurate data Contours between 54 and 56 N rely heavily on the 10km spaced east west tracks surveyed by the US Naval Oceanographic Office in the late 1960s east of 20 W these data were available on the GEODAS CD ROM only a precontoured chart without trackline control was available from this survey west of 20 W Digital tracklines were taken directly from the GEODAS CD ROM and supplemented by the tracklines previously digitised from IOS Sheet 1 Page 63 of 141 AREA 97 3 11 CONTINENTAL MARGIN SOUTHWEST APPROACHES TO THE BRITISH ISLES Source Unpublished series of bathymetric charts compiled by P M Hunter in collaboration with colleagues at the Institute of Oceanographic Sciences IOS Wormley and the Centre Oceanologique de Bretagne COB Brest Compiled on Mercator projection at a scale of 1 250 000 at 38 N with contours at intervals of 100m corrected The charts were compiled over the period 1984 to 1993 and the primary data source was the extensive coverage of Seabeam multibeam echo sounder data 16 adjacent narrow beams within a swathe width below track of approximately two thirds of the water depth collected on NO Jean Charcot and GLORIA Mark II scanning sonar image data maximum scanning range of 30km either side of ship s track from R
97. ction of T E Chase and H W Menard H O Pub No 1302 S US Naval Oceanog Office Barr S M and Chase R L 1974 Geology of the northern end of Juan de Fuca Ridge and sea floor spreading Can J Earth Sci 11 1384 1406 Mammerickx J 1970 Morphology of the Aleutian Abyssal Plain Geol Soc Amer Bull 81 3457 3464 Mammerickx J and Tayler I L 1971 Bathymetry of the Pioneer Survey Area Scripps Institution of Oceanography Sp Chart No 1 Nichols H and Perry R B 1966 Bathymetry of the Aleutian Arc Alaska US Dept Commerce Environmental Sci Services Admin Coast and Geod Survey Mon 3 scale 1 400 000 6 maps Nichols H Perry R B and Kofoed J W 1964 Bathymetry of Bowers Band Bering Sea Jour Surveying and Mapping 24 443 448 Schumaker G M 1976 Bathymetric map of the Aleutian Trench and Bering Sea Map 76 821 US Geological Survey Menlo Park Calif Schumaker G M 1976 Bathymetric map of the Gulf of Alaska Map 76 822 US Geological Survey Menlo Park Calif Schumaker G M 1976 Bathymetric map of the Chukchi Sea and Arctic Ocean Map 76 823 US Geological Survey Menlo Park Calif Sharma G D 1975 Contemporary Epicontinental Sedimentation and Shelf Grading in the southeast Bering Sea Geol Soc of Amer Spec Paper 151 33 48 Stewart R J 1976 Turbidities of the Aleutian abyssal plain Mineralogy provenance and constraints for Cenozoic motion of the Pacific plate Geol
98. d are contours at 500m and at 1000m intervals thereafter Intermediate contours appear frequently on the sheets thus many areas include contours at 100m intervals and some areas include more frequent shallow water contours up to 200m Some of the abyssal floor areas also have contours at 10m 20m intervals NIMA World Vector Shoreline full resolution Page 66 of 141 Published Chart For up to date information on IBCCA chart products please refer to website www ngdc noaa gov mgg ibcca Sheets 1 04 and 1 09 have already been published in hard copy form PREPARATION OF GEBCO SHEET G 03 The bathymetry of the individual IBCCA sheets was compiled and digitized on standard plotting sheets at a scale of 1 500 000 The digital contours for sheets 1 01 to 1 04 were submitted to BODC by Lisa Taylor of NGDC while the contours and trackline control for sheets 1 05 to 1 09 were submitted in digital form by Jose Luis Frias Salazar of INEGI For sheets 1 01 to 1 04 the trackline control was provided in the form of a data source diagram the tracklines and survey box outlines were digitized from this diagram by BODC In order to maintain seamless bathymetry at the standard GEBCO depths i e 200m 500m and at 500m intervals thereafter checks were made by BODC to ensure conformation in the IBCCA contours particularly at 500m 1500m 2500m etc non standard depths within IBCCA Missing contours at these levels were interpolated by BODC with the aid of a
99. d Conservation Monitoring Centre They are the authors of the database Under the auspices of SCAR eight nations Argentina Australia China Germany New Zealand Norway Poland and UK contributed data to the project and three others Japan Russia and USA gave permission for their published maps to be digitised The greater part of the project was funded by the British Petroleum Co The ADD was published by SCAR in 1993 in the form of a single CD ROM accompanied by an extensive 156 page User s guide and reference manual edited by Mrs Janet W Thomson of the British Antarctic Survey This volume also includes a detailed bibliography of all the source material used in the compilation of the ADD The CD ROM has been designed Page 42 of 141 for PC use within the ESRI Environmental Systems Research Institute Inc ArcView software The data may also be viewed and manipulated through ESRI s PC ARC INFO which can be used to transfer the data into other systems Thematic layers present in the ADD include coastlines ice and rock cliffs contours or formline elevations geodetic height data locations of bird or seal colonies glacier flowlines glacier margins isolated ice hillocks or domes outlines of lakes and meltpools outlines of moraines place names from national gazetteers outlines of exposed rock areas meltwater streams tracks of overland traverses historic sites and monuments special protected areas sites of special scient
100. d by latitude Stored in the CONTOURS Directory on disc 2 20 files of the GEBCO trackline control information including tracklines survey box outlines and sounding points complementing the above files of bathymetric contours Stored in the TRACKS Directory on disc 2 10 files of the IBCM First Edition bathymetric contours and coastlines with one IBCM sheet per file Stored in IBCM Directory on disc 2 1 file of GEODAS bathymetric tracklines showing the coverage of echo sounding data held at the IHO Data Centre for Digital Bathymetry as of June 2002 Stored in the GEODAS Directory on disc 2 4 files of SCAR Antarctic Coastlines with one file for each of the scales 1 10 million 1 5 million 1 1 million and the original scale of the source material Each file contains a full coastline with features coded in the range 22010 to 22100 as defined in Table 3 Stored in the SCAR Directory on disc 2 Each of the above directly accessible files is built up as a series of vector streams relating to bathymetric contours coastlines or trackline control information Each file is formatted in the same flat ASCII format as described in Table 2 Each Directory has a readme file describing its contents The Centenary Edition does not contain a directly accessible ASCII version of the World Vector Shoreline WVS Users wishing to obtain their own copy of the WVS or parts thereof in ASCII format are advised to export it throu
101. de P et al 1976 1979 Oceanographic data LBL Pubs 92 251 253 Lawrence Berkeley Laboratory University of California Berkeley California USA Page 17 of 141 ANNEX L 8 GEBCO Sheet 5 08 MAJOR UPDATE NOTE The bathymetry of four regions within the area of GEBCO sheet 5 08 have been replaced by the revised bathymetry contained in a GEBCO sheet G 03 covering Gulf of Mexico Caribbean and the North Atlantic off Florida and the Caribbean from 15 N to 33 N and west of 61 W but only 69 W north of 24 N b GEBCO sheet G 04 essentially north of 32 N and east of 16 W covering the Bay of Biscay and the Atlantic off the Iberian Peninsula c GEBCO sheet G 05 covering an irregular area within the North East Atlantic between 18 N and 35 N 14 W to 47 W d GEBCO sheet G 06 south of 12 N and east of 22 W GEBCO sheet 5 08 was published in January 1982 by the Canadian Hydrographic Service under the authority of the IHO and IOC Scientific Coordinators Cartography by Published Chart Projection Mercator Scale Ellipsoid Southern Limit Western Limit Northern Limit Eastern Limit Note Digitized by Geographic Area Digitized Roger C Searle Institute of Oceanographic Sciences Wormley United Kingdom David Monahan Canadian Hydrographic Service Ottawa Canada and G Leonard Johnson Office of Naval Research Arlington USA Geoscience Mapping Unit Canadian Hydrographic Service GEBCO SHE
102. de la Marine France and soundings sheets compiled by the US Naval Oceanographic Office and the US Defense Mapping Agency Soundings in plotted or computer compatible form were also made available by Institute of Oceanographic Sciences UK Bedford Institute of Oceanography Canada Department of Geodesy amp Geophysics Cambridge University UK Department of Geology Durham University UK Lamont Doherty Geological Observatory USA Shirshov Institute of Oceanology Russia Woods Hole Oceanographic Institution USA The contours were produced at 100m intervals with the soundings corrected according to Matthews Tables Interpolation of contours between sounding lines was based on a geological interpretation of the available data The two published charts were prepared by automatic cartographic techniques developed by NERC s Experimental Cartography Unit Prior to publication the hand drawn contours on the 1 1 million compilation sheets were digitised and stored as labelled streams of coordinates These were subsequently recovered by BODC and after careful checking and editing were used as the basis for constructing GEBCO Sheet 97 3 The trackline control was redigitised by BODC from raster scanned images of the 1 1 million compilation sheets on the continental shelf tracklines are only available in the vicinity of the shelf edge DETAILED SURVEYS INCORPORATED INTO GEBCO SHEET 97 3 G 02 GEBCO Sheet 97 3 includes bathymetry from eleven det
103. depth in corrected metres 50m 100m 200m and at 200m intervals thereafter down to a maximum contour depth of 7800m Also included in the digital data but not on the printed sheets are contours at 500m and at 1000m intervals thereafter NIMA World Vector Shoreline at a scale of 1 250 000 Contours digitized by SHOM with trackline control data provided in the form of sounding points Due to the absence of data from bathymetric surveys some seamounts belonging to Mungo Park Seamounts on IBCEA 1 11 and the Pierre Brazza and Paul du Chaillu Seamounts on IBCEA 1 12 which seem characteristic are included on the sheets based satellite altimetry data Page 82 of 141 PREPARATION OF GEBCO SHEET G 06 The compilation and digitization of the bathymetric contours was carried out by SHOM Available sounding data from collected soundings sheets and single and multibeam surveys were assembled into a digital database with all data corrected according to Echo Sounding Correction Tables publication NP 139 2nd and 3rd editions Hydrographic Office United Kingdom The data were plotted onto 1 250 000 sheets where they were manually contoured at intervals of both 200m and 500m Geomorphological considerations were applied in the contouring and reference was made to satellite altimetry data existing charts and available books reports and archives The contours were then digitized and submitted to BODC to form GEBCO Sheet G 06 the trackline co
104. dert L Delteil J R Valery P Patriat P and Schlich R 1970 Prolongation des zones de fractures de l Ocean Atlantique dans le Golfe de Guinee Earth and Planetary Science Letters 7 413 9 Giresse P Kouyoumonizakis G 1973 Cartographie sedimentologique des plateaux continentaux du Sud Gabon du Congo du Cubinda et du Zaire Cah ORSTOM Paris Ser Geol V 2 235 257 Giresse P 1981 Les sedimentogeneses et les morphogeneses quaternaires du plateau et de la cote du Congo en fonction du cadre structural Bull F A N Dakar Ser A 49 1 2 43 68 Giresse P Kouyoumontzakis G Moguedet G 1979 Le quaternaire superieur du plateau continental congolais Exemple d evolution paleoceanographique d une plate forme depuis environ 50 000 ans In Van Zinderen Bakker E M and Coetzee J A eds Palaeoecology of Africa and the surrounding islands A A Balkema Rotterdam Vol 10 11 193 217 Heezen B C Bunce E T Hersey J B and Tharp M 1964 Chain and Romanche fracture zones Deep Sea Research 11 11 33 Hobart M A Bunce E T and Sclater J G 1975 Bottom Water Flow through the Kane Gap Sierra Leone Rise Atlantic Ocean Journal of Geophysical Research 80 5083 8 Honnorez J Mascle J Basile C Tricart P Villeneuve M and Bertrand H 1991 Mapping of a segment of the Romanche Fracture Zone a morphostructural analysis of a major transform fault of the equatorial At
105. dian Ocean Hartmut Kluger Hydrographic Office Taunton UK Gordon Taylor National Institute of Water and Atmospheric Research Ltd Wellington New Zealand 1997 partial tracks of 15 NIWA cruises between 166 E and 170 E lan Wright Netherlands Institute for Sea Research Texel R V Tyro 1992 1993 cruise Arabian Sea C N van Bergen Henegouw Page 98 of 141 f g h Ocean Research Institute Tokyo 1999 tracks and soundings from ORI s FUJI and INDOYO cruises Kensaku Tamaki Hiromi Fujimoto Tomohiro Yamaashi also Catherine Mevel Laboratoire de Petrologie Mineralogie Metallogenie Paris VI Southampton Oceanography Centre Southampton UK RRS Discovery cruises 199 200 207 208 southwest Indian Ocean Martin Saunders Peter Hunter University of Texas Institute of Geophysics Austin tracks and soundings of Australia s R V Rig Seismic 1994 and of R V Maurice Ewing 1996 Macquarie Ridge Complex Millard Coffin Christina Massell Woods Hole Oceanographic Institution Massachusetts 1987 RRS Charles Darwin Durban Fremantle cruise John Toole National Geophysical Data Centre Boulder Colorado Acquisition updates 1995 1998 Page 99 of 141 ANNEX K 9 GEBCO Sheet G 09 Waters around New Zealand REGIONAL BATHYMETRIC CHART OF NEW ZEALAND compiled 1997 Authors Lionel Carter Greg Foster Richard Garlick John Mitchell and lan Wright Charting Around New Zealand CANZ Group National Insti
106. dopted as the standard GEBCO coastline for all areas south of 60 S and will be incorporated with the GEBCO bathymetry as and when the bathymetry is revised Original Source The Antarctic Digital Database ADD CD ROM published in 1993 by the ICSU Scientific Committee on Antarctic Research SCAR and compiled jointly by the British Antarctic Survey the Scott Polar Research Institute and the World Conservation Monitoring Centre Cambridge UK Update Note Following the CD ROM publication of Version 1 0 of the ADD responsibility for the maintenance and revision of the database was passed to the British Antarctic Survey Version 2 0 was released in July 1998 available over the World Wide Web and including a number of corrections and minor revisions Version 3 0 was released in July 2000 on the WWW and is the version currently in use by GEBCO In Version 3 0 satellite imagery was used to update the position of the fronts of the major ice shelves It also contains improvements in the area of the Antarctic Peninsula including small rock outcrops and islands omitted in the earlier versions From a GEBCO perspective the main revisions compared with Version 1 0 concern the Larsen Wordie Wilkins Ronne and Ross Sea Ice Shelves Stop Press ADD Version 4 0 was released in summer 2002 including a new coastline for the region from 12 E to 168 E provided by the Australian Antarctic Division derived primarily from Landsat images and with a horizontal reso
107. drawn contours were submitted to BODC for digitization and final edge matching The tracklines were submitted to BODC in digital form from a database maintained at SOC Tracklines for data assimilated from hard copy collected soundings sheets were taken from the tracklines already digitized for GEBCO Sheet 5 08 Contouring was carried out as a geomorphological interpretation of the available data and reference was made to the satellite altimetry predictions of Smith and Sandwell 1997 and existing charts The bathymetry for IBCEA Sheet 1 06 was compiled at a scale of 1 250 000 and submitted by SHOM to BODC in digital form although the published chart was based on 200m interval contours additional contours at 500m intervals were provided by SHOM so as to accord with GEBCO standards Edgematching of the contours to surrounding areas in the GEBCO Digital Atlas was carried out at BODC Contours were based on collected oceanic soundings from the following sources a GEBCO Plotting Sheets of Collected Oceanic Soundings up to 1983 Scale 1 1 000 000 Service Hydrographique et Oceanographique de la Marine SHOM Brest France b GEODAS Marine Trackline Geophysical Dataset up to 1998 National Geophysical Data Center NOAA Boulder U S A c Southampton Oceanography Centre formerly Institute of Oceanographic Sciences up to 1998 Natural Environment Research Council U K d Vening Meinesz Laboratorium Kroonvlag Project soundings compilatio
108. e Deep Sea Drilling Projects Vol XLI Jan 1978 Site 366 Sierra Leone Rise 21 29 Site 367 Cape Verde Basin 163 169 Page 87 of 141 Popoff M Raillard S Mascle J Auroux C Basile C et le groupe Equamarge 1989 Analyse d un segment de la marge transformante du Ghana resultats de la campagne Equamarge II mars 1988 C R Acad Sci Paris 309 serie Il 481 487 Quemeneur P 1996 Evaluation des causes d instabilite des sediments sous consolides du talus continental gabonais J Rech Oceanographique 21 1 2 59 64 Robb J M Schlee J and Behrendt J C 1973 Bathymetry of the continental margin off Liberia West Africa Jour Research U S Geol Survey 1 5 563 567 Robert L McMaster Thomas P Lachance and Asaf Ashraf 1970 Continental Shelf Geomorphic Features off Portuguese Guinea Guinea and Sierra Leone West Africa Marine Geology 9 1970 203 213 Searle R C Thomas M V and Jones E J W 1994 Morphology and tectonics of the Romanche transform and its environs Marine Geophysical Research vol 16 427 453 Sheridan R E Houtz R E Drake C L and Ewing M 1969 Structure of Continental Margin off Sierra Leone West Africa Journal of Geophysical Research 74 1969 2512 30 Templeton R M S 1971 The geology of the continental margin between Dakar and Cape Palmas In F M Delany Ed pp 47 60 Tricart P Mascle J Honnorez J Basile C Villeneuve M B
109. e GEBCO Digital Atlas has been obtained from sources believed to be reliable but its accuracy and completeness cannot be guaranteed Whilst every effort has been made to ensure its reliability within the limits of present knowledge no responsibility can be accepted by those involved in its compilation or publication for any consequential loss or damage arising from its use GEBCO is essentially a deep ocean product and does not include detailed bathymetry for shallow shelf waters Even to the present day most areas of the world s oceans have not been fully surveyed and for the most part bathymetric mapping is an interpretation based on random tracklines of data from many different sources The quality and coverage of data from these sources is highly variable Although the GEBCO grid is presented at one minute intervals of latitude and longitude this does not imply that knowledge is available on seafloor depth at this resolution the depth in most one minute squares of the world s oceans has yet to be measured THE GEBCO DIGITAL ATLAS IS NOT TO BE USED FOR NAVIGATION OR FOR ANY OTHER PURPOSE INVOLVING SAFETY AT SEA Page 5 of 141 Useful Websites GEBCO home page http www ngdc noaa gov mgq gebco SCAR Coastline and Antarctic Digital Database http www nerc bas ac uk public magic add_main html World Vector Shoreline http rimmer ngdc noaa gov coast wvs html International Bathymetric Chart of the Arctic Ocean IBCAO http www
110. e chart The digitized contours and digital trackline control data were also submitted to BODC as the base for GEBCO sheet G 09 The bathymetry was compiled from data held at Page 100 of 141 National Institute of Water and Atmosphere NIWA Hydrographic Office of the Royal New Zealand Navy US National Geophysical Data Centre South Pacific Applied Geoscience Commission Fiji from published scientific papers and from recent swath bathymetric surveys funded by Institut Francais de Recherche pour Exploitation de la Mer IFREMER France NIWA and Seabed Mapping New Zealand Ltd The shallow water contours 50m 100m 150m and 200m were delivered to BODC in digital form from the NIWA Coastal Database compiled by Kevin MacKay The database is made up of the digitized contours from the NIWA coastal 1 200 000 chart series Page 10I of 141 ANNEX L Supporting Documentation for GEBCO Fifth Edition sheets used in the GEBCO Digital Atlas General information on the production of the GEBCO Fifth Edition may be found in Annex B while information on the digitization of the GEBCO Fifth Edition sheets for inclusion in the GEBCO Digital Atlas is given in Annex C This Annex contains supporting information to accompany those GEBCO Fifth Edition sheets still used in the GEBCO Digital Atlas It should be noted that the bathymetry from GEBCO sheets 5 09 5 13 and 5 17 has now been superseded by revised bathymetry contained in GEBCO update she
111. e inadvertently omitted in ADD Version 1 0 This is a special case on an ice shelf where the ice is grounded but where the ice is moving with the main mass of the ice shelf rather than having an independent radial flow With the publication of the SCAR Antarctic Digital Database ADD in 1993 a high quality seamless and coherent coastline of Antarctica became available for the first time Not only is it in digital vector form but it also clearly codifies the different types of coastline as listed above and includes a far more comprehensive definition of ice shelf limits than has been available hitherto Compiled from a combination of existing maps and satellite imagery this new coastline is suitable for use at scales of up to 1 1 million in mountainous regions it also includes information up to a scale of 1 250 000 USE OF THE SCAR COASTLINE IN GEBCO For GEBCO purposes it has been decided to standardise the coastline south of 60 S on the SCAR Coastline and to replace the World Vector Shoreline in this area with the SCAR Coastline As there are no coasts crossing the 60 S latitude which is the boundary between the two data sets there are no discontinuities of coastline Furthermore the SCAR Coastline is available at a range of scales compatible with those available in the World Vector Shoreline For use in GEBCO the British Oceanographic Data Centre initially extracted the SCAR Coastline from the Antarctic Digital Database ADD CD ROM
112. eas of the Mid Atlantic Ridge PhD Thesis Department of Geological Sciences University College of London September 1989 402 pp 5 R V Robert D Conrad cruise RC3003 10 February to 12 March 1989 Seabeam survey 6 R V Robert D Conrad cruises RC2515 RC2601 and RC2602 26 December 1984 to 26 February 1985 Seabeam surveys 7 R V Robert D Conrad cruises RC2905 3 April to 26 May 1988 and RC3003 10 February to 12 March 1989 Seabeam surveys 8 R V Robert D Conrad cruise RC2905 3 April to 26 May 1988 Seabeam survey 9 Pogrebitskiy Y Y and Naryshkin G D 1989 Angol Brazil Geotraverse Bathymetric Chart Head Department of Navigation and Oceanography Ministry of Defence and North Branch for Marine Geological Exploration Sevmorgeologia PGO Sevmorgeologia of the USSR Ministry of Geology USSR This chart was used to verify other information 10 Grindley N R Fox P J and Vogt P R 1992 Morphology and Tectonics of the Mid Atlantic Ridge 25 S to 27 30 S from Sea Beam and Magnetic Data Journal of Geophysical Research 97 B5 6983 7010 11 Batiza R Fox P J Vogt P R Cande S C Grindley N R Melson W G and O Hearn T 1989 Morphology Abundance and Chemistry of Near Ridge Seamounts in the vicinity of the Mid Atlantic Ridge 26 S Journal of Geology 97 2 209 220 12 Fox P J Grindlay N R and MacDonald K C 1991 The Mid Atlantic Ridge 31 S to 34 S Tem
113. ectly accessible set of files and software routines Directory CARTER on disc 1 to enable the user to set up his own system for computing the echo sounding correction according to the Third Edition Tables given the ship position and the uncorrected depth reading In addition the GDA Software Interface also provides a facility for automatically computing the echo sounding correction at the geographic position of the cursor on the user s display screen Page 18 of 141 4 0 MAIN FEATURES OF THE GDA SOFTWARE INTERFACE The GDA Software Interface provides the user with wide ranging facilities for displaying querying and exporting data from the various data sets contained in the Centenary Edition of the GEBCO Digital Atlas Many of the data sets can be overlain with each other for simultaneous display The software has been developed to run on an IBM compatible PC operating under Microsoft Windows 95 or later It is controlled by a system of drop down menus and toolbar buttons and requires a minimum of computing expertise on the part of the user The low learning overhead afforded by the system ensures that the novice user is able to operate the Atlas system to good effect almost immediately without the need for special training or for extensive reading of reference manuals An online help system is provided with the software in the form of a hot linked version of the User Guide to the GDA Software which is directly accessible to the use
114. ed that in pursuing its goal of maintaining a global collection of sounding data for the deep ocean the IHO should seek to collaborate with the US NGDC in creating a Page 44 of 141 digital database for sounding data At its meeting in Paris in 1986 the SCDB drafted supporting documentation to facilitate such collaboration In 1987 the US Government submitted a proposal based on the SCDB documentation to the XIIIth International Hydrographic Conference for the establishment of an IHO Data Centre for Digital Bathymetry DCDB to be operated by the US NGDC on behalf of the IHO In 1990 the IHO Member States agreed to this proposal and on 1st June 1990 the IHO DCDB was duly established co located with the US NGDC in Boulder The IHO database of digital single beam echo sounding data is co held within NGDC s GEODAS Geophysical Data System database of worldwide underway geophysics data When the IHO database was first established in 1990 the GEODAS database held over 18 million echo soundings collected on more than 2 500 cruises cruise legs and covering a track distance of 9 3 million nautical miles By June 2002 the IHO DCDB had assimilated a further 23 million echo sounding values covering 5 2 million nautical miles of track into the GEODAS database The total GEODAS database in June 2002 contained some 41 million echo soundings from 4 425 cruises cruise legs covering a track distance of 14 5 million nautical miles The innovative use of co
115. ed to the Roman alphabet where appropriate and English names were used at sea An important innovation with the Fifth Edition was the inclusion of sounding control on the face of each sheet Discrete soundings appear as grey dots and echo sounding tracks as grey lines in the background to the contours Saturated areas and areas of high quality surveys are shown in boxes and cross referenced to a note in the border of the sheet This has enabled far fewer spot depths to be shown in figures indeed these are now virtually confined to maximum and minimum depths of significant features An even greater advantage is that the chart user can assess the contour reliability as a reliable indication of the amount and spacing of the original data from which the contours were drawn is presented It should be noted that a revised version of sheet 5 12 in the South Atlantic was produced in 1994 The GEBCO Guiding Committee decided in 1987 that as the original version of 5 12 printed in 1978 had been based on rather sparse data and as substantial amounts of new data had become available in the meantime it would be in order to commission the preparation of a revised version The compilation and assembly of the contours for the revised sheet was completed in 1993 and it was published by the Canadian Hydrographic Service in 1994 Page 30 of 141 TABLE 1 Sheet No 5 01 5 02 5 03 5 04 5 05 5 06 5 07 5 08 5 09 5 10 5 11 5 12 5 13 5
116. eet 1 01 is limited to a simple source diagram showing the origin of material used in the compilation of the contours in the various areas of the chart unfortunately it does not detail the data coverage available in these areas The source diagram was digitized at BODC together with the references The bathymetry for the Madeira Strait of Gibraltar region Area C was compiled by Peter Hunter at SOC in a series of chartlets at a range of scales from 1 250 000 to 1 500 000 In general the contouring was carried out at intervals of 100m although intervals of 20m or 50m were often used to better describe abyssal plain regions Copies of the hand drawn contours were submitted to BODC for digitization and final edge matching The tracklines were submitted to BODC in digital form from a database maintained at SOC The merging and edge matching of the contours from the three areas to form GEBCO sheet G 04 was carried out at BODC as was the edge matching with the surrounding areas of the GEBCO Digital Atlas DATA SOURCES USED FOR GEBCO SHEET G 04 AREA A Bay of Biscay Extensive multibeam data collected by the IFREMER Centre de Brest including Seabeam data collected from RV Jean Charcot from 1977 to 1983 as compiled in Lallemand et al 1985 and on the Norestlante 3 cruise of 1989 Page 75 of 141 EM12 data acquired on RV Atalante during the 1992 Brest Dakar transit Sibuet et al 1993 the 1991 Sedimanche cruise Bourillet et al 1994 and t
117. eg A P and Twight W 1979 Earth Planet Sci lett 42 103 108 and Collette B J Verhoef J and de Mulder A F J 1980 J Geophys 47 91 98 25 Van Andel Tj H Von Herzen R P and Phillips J D 1971 Mar Geophys Res 1 261 283 26 Ludwig W J and Rabinowitz P D 1980 Mar Geol 35 99 110 27 Francis T J G 1977 In M Angel ed A Voyage of Discovery sup to Deep Sea Res Pergamon Press Oxford 637 645 28 Martin L 1970 Inst of Geol Sciences London Report No 70 16 105 119 Also Martin L 1977 Travaux et Documents de 0 R S T O M No 61 Paris 265 pp 29 Ruffman A Meagher L J and Stewart J McG 1977 Canadian Hydrographic Service Map 839 A Ottawa Page 120 of 141 30 Edelmann P 1979 Topography Morphology of the Continental Margin of Senegal and Mauritania Unpublished survey University of Kiel 31 Wissmann G 1978 Bathmetry of Tioulit canyon and sea knoll Mauritania Unpublished survey Bundesanstalt fur Geowissen schaften und Rohstoffe Hannover 32 Lowrie A Egloff J and Jahn W H 1978 Mar Geol 26 M29 M35 33 Rona P A and Fleming H S 1973 Mar Geol 14 239 252 34 Von Rad U and Wissmann G 1978 Northwest Africa Bathymetry and morphology of the Cape Bojador Continental Margin Unpublished survey Bundesanstalt fur Geowissenschaften und Rohstoffe Hannover 35 Laughton A S 1962 Pap Seamount Unpublished Survey Instit
118. erified depth data were included in the final calculation of the DTM which was then contoured automatically at 50m intervals and plotted out The plots were evaluated against other available geophysical and geological data such as satellite altimetry gravity magnetic tectonic and seismic data Various fabrics resulting from tectonic effects glacial and oceanographic erosion are observed in the Weddell Sea and the contours were adjusted to be consistent with the properties of such fabrics Correlations found in well surveyed areas were used to predict the bathymetry in ice covered areas or to supplement the bathymetry in sparsely surveyed areas If structures in the bathymetry did not appear plausible the reliability of the depth data was re evaluated Reported but unconfirmed or suspect depths were omitted if they conflicted with the morphological evidence of other sources Page 90 of 141 By comparing the depth data with the other data it was possible to verify the plausibility of the sea floor structures together with their extension and orientation The contours were manually adjusted as necessary during this interpretive phase of the compilation particularly in the sparsely sounded areas It should be noted that due to ice cover there is a paucity of soundings in the western central and southern parts of the Weddell Sea and the contours in these regions are somewhat speculative Drafting and final contouring was carried out at scales of 1 1
119. ermany Hilmar Helgason Icelandic Hydrographic Service Harald Brekke and Morten Sand Norwegian Petroleum Directorate Valery Fomchenko Head Department of Navigation and Oceanography Russia Garrik Grikurov and Sergei Maschenkov VNIIOkeangeologia Russia and David Divins National Geophysical Data Center USA 64 N to 90 N 180 W to 180 E WGS 84 Contours derived from a 2 5km by 2 5km bathymetric grid in polar stereographic projection co ordinates Bathymetric depth in corrected metres 20m 50m 100m 150m 200m 300m 400m 500m and at 500m intervals thereafter down to 5500m Additional contours at 100m intervals from 500m to 3400m are also present in southern boundary region between 95 W and 5 E NIMA World Vector Shoreline 1 1 million scale except for the coast of Greenland and northern Ellesmere Island where an updated coastline was provided by the National Survey and Cadastre Denmark KMS Jakobsson M N Z Cherkis J Woodward R Macnab and B Coakley 2000 New grid of Arctic bathymetry aids scientists and mapmakers Eos Transactions American Geophysical Union v 81 no 9 p 89 93 96 PREPARATION OF GEBCO SHEET G 01 The bathymetric contours for sheet G 01 were derived from version 1 0 dated July 2001 of the IBCAO gridded bathymetric data set produced at intervals of 2 5km by 2 5km in polar stereographic projection co ordinates and submitted to BODC by Martin Jakobsson The grid was based on an extensive d
120. ermore a choice of coastlines and coastline scales is offered and if required the user can export data from the IBCM as an alternative or from the GEODAS trackline inventory The choice of data to be included in the output is at the user s discretion When vector streams are exported through the GDA Software Interface the user is offered a choice of formats The vectors can either be exported in the simple flat ASCII format described in Table 2 or in DXF or Shapefile formats as described in Table 4 When exporting coastlines in areas including the Antarctic coast the user can choose either to include the full range of Antarctic coastline feature codes or to use a simplified version just labelling the landward limit of seawater and the seaward limit of floating permanent ice Page 20 of 141 5 3 Directly accessible vector data in ASCII format Exporting vector data through the GDA Software Interface has the advantage that the user can specify a geographic area of interest irrespective of sheet boundaries and can select which features are to be included in the export file However for those users not able to make use of this software the Centenary Edition also contains a directly accessible set of simple flat ASCII files These include 20 files encompassing the full set of GEBCO bathymetric contours and their associated coastlines Each file covers an area of 60 latitude by 60 longitude except that two areas are further sub divide
121. ertrand H et le groupe Equamarge 1989 Etude morphostructurale de la zone de fracture de la Romanche entre 17deg et 18deg W premiers resultats de la campagne Equamarge II 1988 C R Acad Sci Paris t 309 Serie Il 1797 1802 Tricart P Mascle J Basile C Henkhelil J Clais G Villeneuve M 1991 La tectonique d inversion medio cretacee de la marge sud guineenne campagne EQUAMARGE II Bull Soc Geol France Paris t 162 No 1 91 99 Uchupi E Emery K O Bowin C and Phillips J D 1976 Continental Margin off Western Africa Senegal to Portugal American Association of Petroleum Geologists Bulletin 60 809 878 Vanney J R Mascle J 1992 Un canyon sous marin revisite le trou sans fond de Cote d Ivoire Ann geo 562 43 67 Page 88 of 141 ANNEX K 7 GEBCO Sheet G 07 Weddell Sea and the Bransfield Strait BATHYMETRIC CHART OF THE WEDDELL SEA compiled 1997 extended 2001 Update history a subset of this sheet was released as GEBCO sheet 97 2 in the 1997 release of the GEBCO Digital Atlas covering the area of the Weddell Sea south of 65 S and west of 0 W Subsequently updated and extended in the region 60 S to 65 S 75 W to 15 W in the northern Weddell Sea and around the Antarctic Peninsula the Bransfield Strait and westwards Also updated and extended in the region 66 S to 72 S 2 W to 2 E Chief Editors Sheet Limits Scale Horizontal Datum Contour Units Cont
122. etric Chart of the Central Eastern Atlantic IBCEA published by the Instituto Hidrografico Lisbon Portugal on behalf of the IOC and the IHO Published at a scale of 1 1 million Chart Limits 36 N 44 N 15 20 W 7 20 W PREPARATION OF GEBCO SHEET G 04 For the Bay of Biscay Area A Jean Claude Sibuet provided BODC with the 1 1 2 million scale base chart version of the published chart together with a corresponding chart at the same scale showing the multibeam coverage used in its compilation in the form of centre beam tracklines The contours and tracklines were digitized from this material at BODC Trackline information for the conventional soundings was taken from the NGDC GEODAS database although it should be noted that they do not fully represent all the conventional soundings used in the compilation The 500m interval contours i e at 500m 1500m and at 1000m intervals thereafter were interpolated from the 200m contours by Peter Hunter SOC and these were digitized at BODC Prior to its publication the contours for IBCEA Sheet 1 01 were compiled at a scale of 1 250 000 in the form of a digital database at the Instituto Hidrografico Lisbon and a DXF formatted copy of these data were submitted to BODC for incorporating into GEBCO As with the Bay of Biscay chart the 500m interval contours were interpolated from the 200m contours by Peter Hunter SOC and these were digitized at BODC Trackline control information for IBCEA Sh
123. ets G 01 and G 08 Annexes L 9 L 13 and L 17 are therefore missing In the Centenary Edition of the GDA sections of the bathymetry from the Fifth Edition sheets have been replaced by the revised bathymetry in the update sheets G 01 to G 09 The extent of this revision is indicated in parenthesis below Annex L 1 Sheet 5 01 Annex L 2 Sheet 5 02 Annex L 3 Sheet 5 03 Annex L 4 Sheet 5 04 Annex L 5 Sheet 5 05 Annex L 6 Sheet 5 06 Annex L 7 Sheet 5 07 Annex L 8 Sheet 5 08 major updating Annex L 10 Sheet 5 10 major updating Annex L 11 Sheet 5 11 Annex L 12 Sheet 5 12 major updating Annex L 14 Sheet 5 14 major updating Annex L 15 Sheet 5 15 Annex L 16 Sheet 5 16 major updating Annex L 18 Sheet 5 18 major updating major updating partial updating partial updating major updating major updating partial updating ee ee ee ee Page 102 of 141 ANNEX L 1 GEBCO Sheet 5 01 MAJOR UPDATE NOTE The bathymetry in the area of GEBCO sheet 5 01 from 47 N to 64 N 0 to 6 E has been replaced by the revised bathymetry contained in GEBCO sheet G 02 North of 64 N it has been replaced by the revised bathymetry of GEBCO sheet G 01 GEBCO sheet 5 01 was published in April 1978 by the Canadian Hydrographic Service under the authority of the IHO and IOC Scientific Coordinator Johannes Ulrich Institut fur Meereskunde an der Universitat Kiel Germany Cartography by Geoscience Mapping Unit Canadian Hydrogra
124. f 141 ANNEX I Procedures for updating GEBCO Contours The GEBCO Digital Atlas GDA forms the base from which future printed editions of GEBCO will be generated However rather than being geared towards the printing schedules of such future editions the updating of the GEBCO through the GDA will be a continual process Without the scale constraints of the printed chart it is envisaged that improved bathymetric compilations will be merged into GEBCO at scales ranging from 1 10 million up to 1 500 000 or larger scales in isolated cases This will be achieved by stitching in so as to maintain the seamless nature of the data set Use of larger scale material for any given area will be dependent on there being an adequate density of sounding data therein to justify its inclusion In order to maintain the high quality and global nature of GEBCO it is necessary to set standards on the new material used for its updating Prior to their inclusion in the GDA new updated bathymetric compilations in any given area need to conform to the following principles a contours should be expressed in corrected metres b as a minimum the GEBCO basic contours of 200m 500m 1000m and at 500m intervals thereafter should be included Where appropriate the inclusion of contours at 20m 50m and 100m is to be encouraged Where additional intermediate contours are included an interval of 100m is recommended c the GEBCO basic contours should be continuous w
125. f Navigation and Oceanography St Petersburg Russia 1 sheet British Oceanographic Data Centre Bidston UK 2 sheets Quality control final editing and reformatting of these data into a uniform data set was carried out by the British Oceanographic Data Centre BODC Stable base transparencies of the master bathymetric contour plates of the published sheets were used as the source material for digitizing except for sheets 5 06 and 5 12 These transparencies were provided by the Canadian Hydrographic Service at the same scale and projection as the published sheets At each of the participating laboratories the transparencies were raster scanned using laser scanning equipment The raster output typically on a 20 dot mm binary matrix was converted into unlabelled contour vector streams which were then exhaustively checked and edited using an interactive graphics display terminal Gaps in contours caused by contour labels on the published charts were filled in digitally from the terminal Each digitized contour stream was then manually assigned an appropriate bathymetric depth by cross reference to the contours on the printed sheets All bathymetric contours present on the published sheets were digitized including the basic GEBCO contours of 200m 500m and 500m intervals thereafter The actual contours depicted vary considerably from sheet to sheet and intermediate contours are often included to better define the bathymetry in certa
126. fix INT and IOC Regional Ocean Mapping Projects IBCM IBCCA IBCEA and IBCWIO sheets on which the geographical name and the undersea feature are shown or might be added to future editions d where available information on the naming of the feature such as the proposer of the name and the date of the proposal the discoverer of the feature and the date of discovery reference to the GEBCO SCUFN SCGN meeting at which the name was approved and the nature of the supporting evidence and a brief history of the origin of the name Please note that on occasion named features will appear when there is no obvious indication of the feature in the GDA bathymetry In general this implies that the echo sounding data used to identify the feature was not available when the GEBCO contours in the area were compiled Users wishing to obtain a full copy of the IHO IOC Gazetteer of Geographical Names of Undersea Features are directed to the GEBCO website at www ngdc noaa gov mgg gebco where it is available in the form of a spreadsheet It should be stressed that the use of geographic names in the GDA must not be construed as having any legal or political connotation whatsoever They are intended purely for geographic convenience and in the case of undersea features for encouraging the standardisation of names on nautical and bathymetric charts Page 7 of 141 3 5 Inventory of data held at the IHO Data Centre for Digital Bathymetry At an internation
127. gh the GDA Software Interface The Centenary Edition also includes a set of ASCII text files stored in the Directory ASCIIDOC on disc 1 containing the supporting documentation for each of the vector data sets of the GDA including a documentation file for each of the GEBCO sheets This supporting documentation is also accessible through the GDA Software Interface and is also included in the various Annexes of the present User Guide Page 21 of 141 Table 1 Formats for GEBCO Gridded Data The GEBCO One Minute Grid is stored in Directory GRID on disc 1 as one global GMT compatible netCDF data file which may be accessed either directly by the user or through the GDA Software Interface Information concerning netCDF can be found at the URL http www unidata ucar edu packages netcdf The netCDF file is compatible with the GMT Generic Mapping Tools system http gmt soest hawaii edu Within the netCDF format the grid is stored as a one dimensional array of 2 byte signed integer values of elevation in metres with negative values for bathymetric depth and positive values for topographic heights The data values are grid line registered i e they refer to the elevation at the grid points The complete data set gives global coverage It consists of 10 801 x 21 601 data values one for each one minute of latitude and longitude resulting in a total of 233 312 401 points The data start at position 90 N 180 W and are arranged in latitudin
128. h a contour interval of 100m uncorrected The chart was recontoured at intervals of 100m corrected with the contours and trackline control then being transcribed onto the 1 1 million compilation sheets maintained at the Institute of Oceanographic Sciences Wormley UK Later digitised for inclusion in GEBCO Sheet 97 3 AREA 97 3 03 REYKJANES RIDGE CREST SURVEY RRS Discovery cruise 84 1977 unpublished survey by the Institute of Oceanographic Sciences Wormley UK The area was fully surveyed by side scan sonar using the long range 30km double sided sonar of GLORIA Mk II and a hull mounted medium range 2 5km sonar Transects of the ridge were made at intervals of 14km Narrow beam echo soundings were taken on all tracks The tracklines and 100m corrected interval contours were transcribed from the survey sheets onto 1 1 million compilation sheets Later digitised for inclusion in GEBCO Sheet 97 3 Reference Laughton A S Searle R C amp Roberts D G 1979 The Reykjanes Ridge crest and the transition between its rifted and non rifted regions Tectonophysics 55 p 173 177 AREA 97 3 04 OCEAN BASINS AROUND ROCKALL PLATEAU Contours interpolated from unpublished fair drawn bathymetric chart on Mercator projection scaled at 2 inches per degree longitude approx 1 1 million and with a contour interval of 100 fathoms uncorrected Chart produced by the US Naval Oceanographic Office based on Page 61 of 141 a comprehensive echo sou
129. hart bathymetric depth in corrected metres Om 200 500m and at 500m intervals thereafter down to 4500m However for many areas intermediate contours are also included and the digital data set will be found to include contours at the following depths 50m 100m 150m and at 100m intervals from 200m down to 4900m Page 109 of 141 DATA SOURCES USED IN THE COMPILATION OF SHEET 5 04 CONTOURS GEBCO 1 1 000 000 COLLECTED SOUNDINGS SHEETS Canada Canadian Hydrographic Service 1 5C 6 12A 12B 13 14 25A 25B 26 27 40 France Service Hydrographique et Oceanographie de la Marine 39 40 41 42 43 Germany Deutsches Hydrographisches Institut 2 3 7 8 9 14 15 27 28 Iceland Hydrographic Service Charts 25 26 UK Hydrographic Office 7 8 9 14 15 16 27 28 29 40 41 42 43 USA Defense Mapping Agency 38 39 UNPUBLISHED SURVEY DATA OR CONTOURS Canada Canadian Hydrographic Service Denmark Royal Danish Hydrographic Office German cruises 1970 and 1972 by R V Meteor and 1971 by R V Komet UK cruises 1973 and 1974 of RRS Shackleton by Durham University UK Institute of Oceanographic Sciences 1 1 000 000 bathymetric charts 2 3 7 8 9 14 15 16 27 28 29 40 41 42 43 UK Hydrographic Department US Defense Mapping Agency USSR Cruises 11 and 15 of R V Kurchatov USSR site surveys for DSDP Leg 38 SCIENTIFIC LITERATURE Egloff J and Johnson G L 1975 Can J Earth Sci 12 12 2
130. he 1992 Zeegasc cruise Pautot et al 1995 Conventional sounding data were acquired primarily from Service Hydrographique et Oceanographique de la Marine SHOM France GEBCO Plotting Sheets 42 and 43 up to 1989 Vening Meinesz Laboratorium Kroonvlag Project soundings compilations at 1 1 000 000 scale University of Utrecht The Netherlands The following were also consulted Lallemand S Maze J P Monti S and Sibuet J C 1985 Presentation d une carte bathymetrique de l Atlantique nord est C R Acad Sc Paris Serie Il 300 4 145 149 Bathymetric map scale 1 2 4 million published by IFREMER France Laughton A S Roberts D G and Graves R 1975 Bathymetry of the northeast Atlantic Mid Atlantic Ridge to southwest Europe Deep Sea Research 22 791 810 and Admiralty chart C6568 scale 1 2 4 million DATA SOURCES USED FOR GEBCO SHEET G 04 AREA B IBCEA Sheet 1 01 IBCEA Sheet 1 01 includes a data source diagram where the data source s for each area are numerically referenced as follows 1 Vanney J R Rothwell R G et al Groupe Transmarge 1984 Leve bathymetrique a l aide du sondeur multifasceaux SEABEAM du versant septentrional du Banc de Galice marge continentale ouest iberique Comptes Rendus Academie des Sciences Paris Serie Il 299 3 115 120 2 Rojouan F 1985 Thesis Universite de Paris Sorbonne France 3 Multibeam contours of Galicia Bank Tore Seamount Gorringe Bank
131. hed by UK Hydrographic Department Taunton at a scale of 1 250 000 with depths contoured at 5 fathom corrected intervals Based on detailed survey carried out by HMS Hecla in 1969 consisting of regular east west bathymetric transects of the Bank with a spacing of 2 75km but with 1 4km line spacing in areas of rough bottom topography with depths less than 100 fathoms and a 0 7km line spacing in the immediate vicinity of Rockall Islet Navigated by Loran C with estimated fix accuracy of 200m For inclusion in GEBCO Sheet 97 3 the published chart was recontoured at intervals of 50m corrected and then digitised at a scale of 1 500 000 The tracklines were digitised from a 1 1 million scale chart in the reference below Reference Roberts D G amp Jones M T 1978 A bathymetric magnetic and gravity survey of the Rockall Bank by HMS Hecla 1969 Admiralty Marine Science Publication No 19 Hydrographic Department Taunton AREA 97 3 10 ROCKALL PLATEAU Contours were digitised directly from an unpublished bathymetric chart compiled in 1996 by P M Hunter of the Southampton Oceanography Centre UK The chart was compiled on Mercator projection at a scale of 1 1 million with contours drawn at intervals of 100m corrected Based primarily on single beam soundings available on the GEODAS Version 3 CD ROM published in June 1995 by the US National Geophysical Data Center Boulder IHO Data Centre for Digital Bathymetry Contours were drawn to be
132. henke b L Ecole et Observatoire de Physique du Globe de Strasbourg track and soundings of R V Marion Dufresne and R V l Atalante in central and eastern Indian Ocean 1980 1998 Marc Munschy Marc Schaming Roland Schlich Marie Odile Boulanger c Institut Universitaire European de la Mer Universite de Bretagne Occidentale Plouzane 1998 MAGOFOND 2 cruise of R V Marion Dufresne Jerome Dyment R V Marion Dufresne 110 and R V Atalante TASMANTE 1994 cruises J Y Royer d Laboratoire de Geophysique Marine Institut de Physique du Globe de Paris Paris VI R V Marion Dufresne and R V L Atalante 1982 1995 sounding data in the western and east central Indian Ocean Philippe Patriat Jacques Segoufin e R V Melville SIO soundings in the southeast Indian Ocean 1994 1995 contributions from Lamont Doherty Earth Observatory New York Christopher Small James Cochran Carl Brenner Oregon State University David Christie University of Washington Jean Christophe Sempere f Geological Data Center Scripps Institution of Oceanography La Jolla California Alliance exotique IODCP files 1987 2001 Virginia Wells Secondary sources digital files Bullard Laboratories University of Cambridge UK 1986 1987 cruises of RRS Charles Darwin RRS Shackleton Carol Williams Bundesamt fur Seeschiffahrt und Hydrographie Hamburg 1997 tracks and soundings being compiled for OC s International Bathymetric Chart of the Western In
133. ho were nominated after consultation with the Scientific Committee on Oceanic Research SCOR the International Association for the Physical Sciences of the Ocean IAPSO and the Commission for Marine Geology CMG were eminent marine geologists and geophysicists The IHO retained responsibility for maintaining the 655 collected soundings sheets on a scale of 1 1 million and for providing cartographic advice on and supervision over the final product On the other hand the IOC in conjunction with SCOR IAPSO and CMG was responsible for all scientific input including contouring of the bathymetric data and compilation of the final waterwork for each sheet The collected soundings sheets provided by the volunteering Hydrographic Offices formed a unique data base on which to compile the Fifth Edition However by virtue of the fact that these sheets had been compiled over a period of thirty to forty years the data recorded thereon varied considerably in accuracy both in depth and position depending on the sounding apparatus fitted in and the navigational methods employed by the numerous ships which had contributed data Improved methods of sounding by Precision Depth Recorder using a crystal controlled time base and navigation using such systems as Omega and the Satellite Navigator clearly demonstrated the errors to which earlier data were liable However in the absence of improved modern data these data continue to be all that are availa
134. ic Oceanographic and Meteorological Laboratories 1976 Tracks confined to the area 69 to 77 W 26 to 29 N Bathymetric chart of the Blake Escarpment at a scale of 1 1 000 000 Universal Transverse Mercator compiled by William P Dillon of the U S Geological Survey unpublished Imagery from the side scanning sonar system GLORIA II obtained by the U S Geological Survey for the Blake Escarpment was employed in interpretation of bathymetric contours The GLORIA II imagery was custom photographed to scale and provided by William P Dillon of the U S Geological Survey U S Naval Oceanographic Office bathymetric contour sheet 805 NA 9 at a scale of 1 1 000 000 compiled by F H Sorensen in 1984 provided supplementary information in areas of sparse track control particularly in the area of 24 N to 24 30 N 74 30 W to 76 30 W IBCCA SHEET 1 05 Scientific Coordinator Jose Luis Frias Salazar DGG INEGI Compilers Marcos Aguilar Benitez Manuel Cruz Pineda DGG INEGI Digital soundings from the U S National Geophysical Data Center Global Trackline Geophysical Data Base GEODAS Sources of detailed surveys and bathymetric contours 1 Southern area of the Bay of Campeche Bathymetric contours taken from the 1 200 000 scale maps Marbella and Coatzacoalcos produced from Mexican Petroleum s Marine Seismology Program The spacing between sounding lines is approximately 4km 2 Survey off Pacific coast of
135. ic and Atmospheric Administration National Ocean Service survey ships PEARCE WHITING and MONT MITCHELL Locally these surveys were supplemented by trackline bathymetry from the files of the U S National Geophysical Data Center Bathymetric Chart of the Eastern Caribbean at a scale of 1 1 000 000 compiled by P Bouysse 1984 and published in Philippe Bouysse Patrick Andreieff Maryannick Richard Jean Claude Baubron Alain Mascle Rene Charles Maury and Denis Westercamp 1985 Geologie de la Ride d Aves et des Pentes Sous Marines du Nord des Petites Antilles Documents du BRGM no 93 146 p maps In addition to the trackline shown data from draft bathymetry at a scale of 1 100 000 west of Guadaloupe from the Atlantic Oceanogaphic Mission B H d Entrecasteaux Service Hydrographique et Oceanographique de la Marine contributed in 1981 by H Got of the University of Perpignan as well as miscellaneous navigation charts of the Hydrographic Offices of France U S A and the United Kingdom for certain island plateaus and submarine banks of the Lesser Antilles and the Anegada Passage were used in the compilation of this area U S Naval Oceanographic Office surveys trackline spacing 1 10 km Adapted from bathymetric contours by James E Matthews and Troy L Holcombe compiled at a scale of 1 1 000 000 and published at a scale 1 2 000 000 in Mathews J E and Holcombe T L 1976 Regional Geological Geophysical Study of the Caribbean Sea Nav
136. ific interest and a layer relating to sites of human activity Copies of the ADD CD ROM and its supporting volume may be obtained from Executive Secretary Scientific Committee on Antarctic Research Scott Polar Research Institute Lensfield Road Cambridge CB2 1ER United Kingdom The ADD is maintained by the Mapping and Geographic Information Centre MAGIC of the British Antarctic Survey Although Version 1 0 of the ADD was published on CD ROM subsequent versions have been made available on the World Wide Web Web address www nerc bas ac uk public magic add_home In the changeover to Web delivery the database has been transferred from PC Arc Info format to Workstation Arc Info format Page 43 of 141 ANNEX F IHO Data Centre for Digital Bathymetry DCDB The first international system for compiling sounding data on a worldwide basis was established in 1903 by HSH Prince Albert of Monaco Following his death in 1922 the Government of Monaco invited the International Hydrographic Bureau now the International Hydrographic Organization to take over the scheme In 1929 the Bureau was entrusted with this task by the International Hydrographic Conference and a world series of Ocean Plotting Sheets was established at a scale of 1 1 million on Mercator projection on which to record and publish all sounding data outside the continental shelf Up until World War Il the data was comparatively sparse and could be handled by the s
137. imilar manner to the trackline control information associated with the GEBCO bathymetry This information is included in the Centenary Edition of the GDA both in a form for user selected display export through the GDA Software Interface and as stand alone ASCII files for direct access by the user 3 6 Echo sounding correction tables Measurements of seafloor depths using echo sounding techniques depend on knowledge of the mean velocity of sound in the water column between the echo sounding device and the seafloor This in turn is dependent on the temperature and salinity down the water column and these characteristics vary across the world s oceans Most modern echo sounders assume a sound speed of 1500 m s while some earlier versions assume 800 fm s 1463 m s Since 1929 when the First Edition of Matthews Tables was published standard correction tables have been used to correct for the true speed of sound in seawater for this purpose the world s oceans are divided into discrete areas linking regions with common sound velocity profiles and a table is constructed for each area with the depth correction to be applied at various depths down the water column In 1980 a Third Edition of the Echo Sounding Correction Tables see Annex H was published by the U K Hydrographic Department to replace Matthews Tables and these were adopted in 1982 by the XIIth International Hydrographic Conference at Monaco The Centenary Edition of the GDA contains a dir
138. imple interface for exporting user selected data into their own applications The complete package is available from National Geophysical Data Center NOAA E GC3 325 Broadway Boulder CO 80303 3328 U S A Fax 1 303 497 6513 Email Robin R Warnken noaa gov Website www ngdc noaa gov mgg geodas Page 45 of 141 ANNEX G Geographic Names in the GEBCO Digital Atlas BACKGROUND Since its inception at the turn of the century GEBCO has been intimately concerned with the nomenclature and terminology used for the naming of undersea features It plays an international role in the naming of undersea features falling entirely or mainly more than 50 outside territorial waters In 1974 the GEBCO Guiding Committee established a Sub Committee on Geographical Names and Nomenclature of Ocean Bottom Features renamed in 1993 the GEBCO Sub Committee on Undersea Feature Names with the main objective of advising on names and nomenclature to be used on the GEBCO charts The Sub Committee developed a list of definitions for undersea feature terms which were subsequently discussed with the Working Group on Maritime and Undersea Features of the United Nations Group of Experts on Geographical Names As a result of these discussions a set of joint guidelines together with principles and procedures for naming features a name proposal form and a list of terms and definitions was worked out in accordance with the provisions of appropriate resolution
139. in regions However all sheets include as a minimum the basic GEBCO contours and these were digitized as closed contours without open ends All contour levels are expressed in corrected metres i e based on echo soundings corrected for the speed of sound according to the Echo Sounding Correction Tables On occasions where it was difficult to identify contour values without ambiguity reference was made back to the Scientific Co ordinator s for the sheet the IHO collected soundings sheets or the digital sounding data held at the National Geophysical Data Center Boulder USA Prior to their final release the digitized contours for each sheet were reviewed in detail at BODC This review involved plotting out the contour vectors on the same scale and projection as the published sheet and checking out in detail the registration and labelling of each vector no mean feat considering that the 18 Fifth Edition sheets produced some Page 33 of 141 95 000 contour segments BODC s checks on the digitized sheets confirmed that the techniques adopted at the participating laboratories were able to reproduce the Fifth Edition contours to an accuracy comparable with the line thickness of the contours on the published sheets As already mentioned the digitization was carried out on a sheet by sheet basis Where the published sheets overlap in geographic coverage only one version of the overlapping area was digitized i e that shown on the most recently
140. ional contours at the following depths 100m 800m 1600m 1800m 2100m and at 100m intervals thereafter down to 5800m with one additional contour at 6100m Page 15 of 141 Comments The digitized data for this chart were edgematched with that for GEBCO sheets 5 03 5 06 5 10 and 5 11 with the result that some of the contours at the sheet boundaries may be displaced slightly from their positions on the published chart As the digital data for GEBCO sheet 5 06 were supplied from a regularly updated data base and not digitized from the original sheet it proved difficult to achieve an edgematch with the digital data for GEBCO sheet 5 07 most notably in the following areas 1 34 30 to 35 30 N 180 W 2 41 30 to 43 N 180 W DATA SOURCES USED IN THE COMPILATION OF SHEET 5 07 CONTOURS Defense Mapping Agency Hydrographic Topographic Center Washington D C Hawaii Institute of Geophysics University of Hawaii Honolulu Hawaii Lamont Doherty Geological Observatory Columbia University Palisades New York National Geophysical and Solar Terrestrial Data Center Boulder Colorado Naval Oceanographic Office NSTL Station Bay St Louis Mississippi School of Oceanography Oregon State University Corvallis Oregon Scripps Institute of Oceanography University of California San Diego California SCIENTIFIC LITERATURE Bathymetric Maps of the sea floor off the west coast of the United States 1967 1975 US Coast and Geodetic
141. ironment with projection parameters set to polar stereographic on the WGS 84 ellipsoid with a true scale at 75 N The data were corrected for sound velocity using Carter s Tables or CTD profiles where available and colour coded by depth value to facilitate a visual inspection of outliers cross track errors and the fit between contours and sounding data Suspicious soundings were removed and where contours showed major discrepancies with the soundings the contours were manually adjusted to fit the new trackline data All data were then exported to an XYZ co ordinate system for further processing and for gridding using the GMT public domain software Prior to gridding the data were pre processed with a block median filter in GMT Gridding at a cell size of 2 5 x 2 5km was performed with the surface program fitting a surface of continuous curvature to all points Three dimensional visualization of the gridded data highlighted discrepancies that had to be resolved in the input data set after which the data were re gridded and re inspected for residual discrepancies This process was continued until the results were deemed satisfactory For the creation of GEBCO sheet G 01 contours were generated from the 2 5 x 2 5km grid using Z I Imaging s tool Modular GIS Environment MGE Terrain Analyst MTA A cubic parametric curve was fitted through the generated contours for removal of minor deviations along the contour lines The contour nodes
142. ismic measurements in the New Zealand region New Zealand Journ of Geol and Geophys 20 719 777 Davey F J 1981 in press Geophysical studies in the Ross Sea region Jour of Royal Society of New Zealand 11 4 Deighton l Falvey D A and Taylor D J 1976 Depositional environments and geotectonic framework Southern Australian continental margin Australian Petroleum Exploration Assoc Journ 25 36 Falconer R K H and Falconer R F 1981 in press Seismicity Fracture zones and poles of rotation of the Pacific Antarctic and Indian Antarctic plate boundaries Third Antarctic Geology and Geophysics Symposium University of Wisconsin Press Hayes D E Frakes L A et al 1975 Initial Reports of the Deep Sea Drilling Project Volume 28 1017 app Hayes D E and Talwani M 1972 Geophysical investigation of the Macquarie Ridge Complex In D E Hayes Ed Antarctic Oceanology II Antarctic Res Ser 19 Amer Geophys Union 211 234 Heezen B C Tharp M and Bentley C 1972 Morphology of the Earth in the Antarctic and Subantarctic In Antarctic Map Folio Series 15 Amer Geographic Soc 16 pp 8 pl Kennett J P 1977 Cenozoic evolution of Antarctic glaciation the circum Antarctic oceans and their impact on global paleoceanography Jour of Geophys Res 82 3843 3860 Johnson G L Vanney J R and Hayes D E 1981 in press The Antarctic Continental Shelf Third Antarctic Geology and Geophysics Sym
143. issance of the eastern Mediterranean In the eastern Mediterranean east of 20 E the Department of Geodesy and Geophysics of Cambridge University carried out a regional bathymetric survey with another 220 000 km of track These 550 000 km of track comprised 80 of all the data available for the First Edition of the IBCM The cartography of the First Edition of IBCM was carried out by the Head Department of Navigation and Oceanography St Petersburg and they published the complete series in 1981 under the auspices of the IOC It consists of 10 sheets on Mercator projection at a scale of 1 1 million at 38 N and covers an area 30 N to 46 N 6 W to 36 5 E The Black Sea is included at a scale of 1 2 million for the area 40 N to 47 5 N 26 5 E to 42 5 E Most sheets depict contoured bathymetry at Om coastline 20m 50m 100m and 200m and at 200m intervals thereafter although the actual contours displayed vary slightly from sheet to sheet The published sheets also include land contours as well as sounding control showing the position of echo sounding tracks and areas of detailed surveys The IBCM coastline was taken from the original bathymetric plotting sheets except for Corsica Sardinia and the area of Alexandria where the coastline shown on the plotting sheets differed significantly from that on the nautical charts and topographic charts available at the time IBCM was in preparation The coastline was taken from the latter for these area
144. issenschaftliche Berichte Marine Science Reports Institut fur Ostseeforschung Warnemunde Germany Page 58 of 141 ANNEX K 2 GEBCO Sheet G 02 NE Atlantic off the British Isles BATHYMETRY OF THE NORTH EAST ATLANTIC OFF THE BRITISH ISLES compiled February 1997 and originally published as sheet 97 3 in the 1997 release of the GEBCO Digital Atlas Minor update note The bathymetry between 47 N and 48 N in the regions 11 5 13 W and 0 7 5 W has been replaced by revised bathymetry from GEBCO sheet G 04 Author Sheet assembled by Peter M Hunter Southampton Oceanography Centre U K from bathymetric charts compiled at the Institute of Oceanographic Sciences Wormley Surrey U K Note The Institute of Oceanographic Sciences laboratory at Wormley was relocated to the Southampton Oceanography Centre in 1995 Sheet Limits 47 N to 64 N 37 W to 6 E Scale Contours compiled and digitised at a scale of 1 1 million but up to 1 250 000 in certain limited areas Horizontal Datum WGS 84 Contour Units Bathymetric depths in corrected metres Contours present 100m intervals throughout the area of the sheet down to a maximum contour depth of 5000m Contours at 50m intervals on Rockall Bank Coastline Source NIMA World Vector Shoreline at a scale of 1 1 million Digitised by NERC Experimental Cartography Unit British Oceanographic Data Centre and the Southampton Oceanography Centre BASE MAP FOR GEBCO SHEET 97 3 G 02 The
145. ithin the compilation area d contours cutting the edges of the compilation area should be stitched in to those in the surrounding area of the GDA in general the stitching in should be from outside the compilation area rather than from inside e in coastal zones and around islands the contours should be compatible with the World Vector Shoreline or the SCAR coastline of Antarctica f compilations submitted should be accompanied by the ship tracks and survey boxes annotated with their source used in compiling the contours g the updating material should normally consist of digital contours if submitted in hard copy form sufficient graticule points should be included within and at the edges of the map to enable potential distortions to be checked through subsequent digitizing and if necessary corrected h compilation methods should be fully described in supporting documentation including details of the projection ellipsoid and scale used as well as information on any additional support material that might have been used e g magnetic surveys sonar images satellite altimetry proprietary compilations the names and affiliation of the authors of the map the data sources used and the date the map was compiled i in international waters the names of newly named undersea features should be submitted for approval to the GEBCO Sub Committee on Undersea Feature Names or to the appropriate national authority where they fall
146. ities in the Weddell Sea in 1983 using the ice breaking research vessel RV Polarstern few soundings were available for compiling a bathymetric chart of the area Since then more than 40 expeditions have taken place in the region including more than 20 cruises of RV Polarstern with continuous multi beam echo sounding using either Seabeam or Hydrosweep systems Area A is based on the Polarstern data and on additional echo sounding data supplied by several national Hydrographic Offices and research institutions Due to the hostile nature and high latitude of the area the data coverage is very irregular and the quality of the data is highly variable with navigation uncertainties and recording errors Digital Terrain Modelling DTM techniques were used to assist in the assimilation of the soundings Prior to final acceptance each track of data was verified by checking for crossover errors and for reasonable navigation e g checking ship speed and by comparing the data with the developing DTM with neighbouring soundings and with the morphological fabric of the area Obviously erroneous data were corrected if possible e g by adjusting the navigation or eliminated During the verification the data were assigned a quality factor for use in weighting the contribution of the data in the construction of the DTM Within the DTM the grid size varied from 0 5 to 2 5 n miles depending on the data density and the complexity of the underlying topography All v
147. itising interpreted vector data direct from photographic products of Landsat multi spectral scanner scenes at 1 500 000 scale Features identified on each scene and on the corresponding published maps of the area where available provided control for the photo mosaic The digital coastline vectors covering the Filchner Ronne Ice Shelf and parts of Ellsworth Land Coats Land and western Neuschwabenland between 80 W and 5 E were prepared by the Institut fur Angewandte Geodasie Frankfurt am Main and the Alfred Wegener Institut fur Polar und Meeresforschung Bremerhaven These were derived from a geocoded raster mosaic of Landsat multi spectral scanner images with a scale of data capture of 1 400 000 Reference was made to other sources as appropriate For example due to recent changes to the ice front of the Ross Ice Shelf reference was made to Keys H J R Jacobs S S amp Barnett D 1990 The calving and drift of iceberg B 9 in the Ross Sea Antarctica Antarctic Science 2 3 p 243 257 THE ANTARCTIC DIGITAL DATABASE ADD Although the GEBCO interest in the ADD is primarily as the source of a high quality Antarctic coastline it should be noted that the ADD is a comprehensive within the limits of present knowledge GIS orientated topographic cartographic database of the Antarctic continent The ADD was created by a Cambridge UK consortium consisting of the British Antarctic Survey the Scott Polar Research Institute and the Worl
148. l names as and when they are approved by the GEBCO Sub Committee on Undersea Feature Names SCUFN A copy of the IHB database was used as the source material for the undersea feature names in the GDA and it includes all names approved by the GEBCO SCUFN up to September 2002 Information extracted from the Gazetteer for each undersea feature and which may be viewed on the user s screen when the feature is queried through the GDA Software Interface includes a the geographical name of the feature and the generic term used to define the nature of the feature b the geographical position of the feature this is only an approximate position and is used solely to identify the feature rather than to define its precise location Where the feature is extensive a second position may also be given to indicate its extent For linear features such as ridges and fracture zones further positions may have been added by BODC to delineate the feature c areference to the GEBCO sheets IHO Small Scale International Charts using the prefix INT and IOC Regional Ocean Mapping Projects IBCM IBCCA IBCEA and IBCWIO sheets on which the geographical name and the undersea feature are shown or might be added to future editions Page 47 of 141 d where available information on the naming of the feature such as the proposer of the name and the date of the proposal the discoverer of the feature and the date of discovery reference to the GEBCO SCUFN SCG
149. la campagne Equamarge Soc geol France 8 t Ill no 5 877 885 Bonvrelot S Pontoise B Mascle J 1989 Structure profonde de la marge continentale sud guineene apport des donnees gravimetriques C R Acad Sci Paris t 309 1915 22 Burke K 1972 Longshore drift submarine canyons and submarine fans in development of Niger delta American Association of Petroleum Geologists Bulletin 56 10 1975 1983 Cochonat P Droz L Geronimi C Guillaume J Loubrieu B Ollier G Peyronnet J P Robin A Tofani R and Voisset M 1993 Morphologie sous marine du secteur oriental du delta du Niger golfe de Guinee C R Acad Sci Paris 317 serie Il 1317 1323 Chauveau E 1994 Les marges continentales de Guinee et de Cote d Ivoire orientale Etude de geomorphologie sous marine These de Doctorat d Universite Paris IV Sorbonne 343 p Egloff J 1972 Morphology of the Ocean Basin Seaward of Northwest Africa Canary Island to Monrovia Liberia American Association of Petroleum Geologists Bulletin 56 694 706 Emery K O Uchupi E Phillips J Bowin C and Mascle J 1975 Continental Margin off Western Africa Angola to Sierra Leone American Association of Petroleum Geologists Bulletin 59 2209 65 Equipe Guiness 1993 Morphologie sous marine du secteur oriental du delta du Niger golfe de Guinee C R Acad Sci Paris Ser Il 317 1317 1323 Page 85 of 141 Fail J P Monta
150. laboration with the British Oceanographic Data Centre Geographic Area Digitized The digital data in this file covers the area 90 to 180 E 0 to 46 40 N Please note 1 2 3 The bathymetric contours for most of this area were kept updated by Dr Iwabuchi at the Japan Oceanographic Data Center and a new compilation was produced in 1984 in the form of a paper atlas published on Mercator projection at a scale of 1 1 million covering the area 120 to 180 E 0 to 46 40 N Thus rather than digitize the outdated information published as GEBCO sheet 5 06 in 1979 it was decided to make use of digital files already available from JODC The digital data for the area 120 to 180 E 0 to 46 40 N were supplied by JODC from a data base digitized from source material at a scale of 1 1 million The source material for this area is covered in the paper atlas published in 1984 and supplied by JODC A 1 1 million digital data set covering the area 100 to 120 E 0 to 46 40 N was also supplied by JODC Quality control work on the digital data sets supplied by JODC was carried out at BODC The volume of data was reduced using software based on the Douglas Peucker generalization algorithm A lateral tolerance factor of 0 08mm was Page 13 of 141 used The use of this filtering algorithm reduced the size of the data file to approximately 11 2 percent of its original volume 4 The digital data for the area 90 to 100 E 0 t
151. lantic Ocean Geology 19 795 798 Hospers J 1971 The geology of the Niger delta area In F M Delany Ed The Geology of the East Atlantic Continental Margin Vol 4 Africa ICSU SCOR Working Party 31 Symp Cambridge Rep No 70 16 Inst Geol Sci London 124 142 Jansen J H F Giresse P Moguedet G 1984 Structural and sedimentary geology of the Congo and Southern Gabon continental shelf a seismic and acoustic reflection survey Netherlands J Sea Res 17 2 4 364 384 Jones E J W and Mgbatogu C C S 1982 The structure and evolution of the West African continental margin off Guine Bissau Guinee and Sierra Leone In R A Scrutton and M Talwani Eds The Ocean Floor 165 202 Jones E J W 1987 Fracture zones in the equatorial Atlantic and the breakup of western Pangea Geology 15 533 36 Jones E J W Goddard D A Mitchell J G and Banner F T 1991 Lamprophyric volcanism of Cenozoic age on the Sierra Leone Rise Implications for regional tectonics and the stratigraphic time scale Marine Geology 99 19 28 Jones E J W and Mgbatogu C C S 1982 The structure and evolution of the West African continental margin off Guine Bissau Guinee and Sierra Leone The Ocean Floor 165 202 Krause D C 1963 Seaward extension and origin of the Freetown layered basic complex of Sierra Leone Nature London 200 1280 1 Krause D C 1964 Guinea fracture zone in the Equatorial Atlantic Science 1
152. le du Monde of the Institut G ographique National in Paris France and for the Antarctic continent on maps provided by the Scott Polar Research Institute in Cambridge England However there are two exceptions a forthe region 50 S to 7 N 70 W to 20 E of revised GEBCO sheet 5 12 the digital coastline was taken from the high resolution World Vector Shoreline digital data set reduced in volume by 84 using the Douglas Peucker algorithm with a lateral tolerance of 0 04mm at a scale of 1 5 737 447 b for the region 0 N to 46 40 N 100 E to 180 E the coastline was provided in digital form by the Japan Oceanographic Data Center based on their standard 1 1 million bathymetric charts of the region The volume of this data set was reduced by 89 using the Douglas Peucker algorithm with a lateral tolerance of 0 08mm Recognising that the digitized contours would be of limited value without corresponding information on the distribution of soundings used in their original compilation it was decided that the trackline control should also be digitized from the Fifth Edition sheets Using almost identical techniques and procedures to those used in digitizing the bathymetric contours and coastlines the tracklines from the Fifth Edition were digitized on a sheet by sheet basis by three organisations in Russia Germany and the UK thus British Oceanographic Data Centre Bidston UK 13 sheets Head Department of Navigation and Oceanography S
153. ler Meeresforshungen 16 155 163 van der Linden W J Fillon R H and Monahan D 1976 Geol Surv Can Paper 75 40 31 pp Vogt P R and Avery O E 1974 J Geophys Res 79 2 363 389 Vogt P R and Johnson G L 1972 Earth and Plan Sci Letters 15 248 254 Vogt P R and Johnson G L 1975 J Geophys Res 80 1399 1428 Vogt P R Johnson G L Hollombe T L Gilg J G and Avery O E 1971 Tectonophysics 12 3 211 234 Page 11 of 141 ANNEX L 5 GEBCO Sheet 5 05 MAJOR UPDATE NOTE The bathymetry of virtually all of the area of GEBCO sheet 5 05 has been replaced by the revised bathymetry contained in GEBCO sheet G 08 Essentially all that remains from sheet 5 05 is the bathymetry of the Red Sea GEBCO sheet 5 05 was published in April 1975 by the Canadian Hydrographic Service under the authority of the IHO and IOC Scientific Coordinator Cartography by Published Chart Projection Mercator Scale Ellipsoid Southern Limit Western Limit Northern Limit Eastern Limit Note Digitized by Contour Units Contours Present Anthony S Laughton Institute of Oceanographic Sciences Wormley United Kingdom Geoscience Mapping Unit Canadian Hydrographic Service GEBCO SHEET 5 05 April 1975 1 to 10 million at the Equator International 1924 Hayford 00 00 N 006 00 W 46 40 N 100 00 E The area from 90 to 100 E is only covered between 0 and 32 N The area 0 to 6
154. lution of 50m Landsat images have also been used to improve the coastline of the northern part of the Antarctic Peninsula north of 68 S These revisions have not yet been incorporated into the GEBCO Digital Atlas Coverage Antarctica and surrounding islands out to 60 S Scale Coastline compiled at a range of scales from 1 200 000 to 1 1 million depending on availability of detailed maps and imagery INTRODUCTION The US National Imagery and Mapping Agency s World Vector Shoreline has been adopted as the standard coastline for use in the updating of GEBCO Not only is it a high quality product suitable for use at scales of up to 1 250 000 but it has global coverage and is available in digital form Unfortunately it is known to be inaccurate around the Antarctic continent but more significantly it does not deal effectively with the presence of ice in the coastal zone In non polar regions of the world the coastline is simply the boundary between the land and the sea Being coincident with mean sea level it also acts as the zero depth contour However around Antarctica the concept of a coastline is more complex and needs to represent the boundary between three domains viz land sea and ice shelf Along a significant part of the Antarctic coast there is a fringe of permanent floating ice called the ice shelf Note that the ice shelf does not include the offshore seasonal ice sheet sea ice that breaks up every year Page 38 of 1
155. mall staff at the disposal of the Bureau By the mid 1950s a great wealth of modern data became available and it was clearly beyond the resources of the Bureau alone to maintain the soundings data bank Consequently in order to ensure that the 1 1 million plotting sheets could be kept up to date a network was established involving the services of volunteering Hydrographic Offices in 18 IHO Member States Each of the Volunteering Hydrographic Offices VHOs accepted responsibility for compiling bathymetric data in specific geographic areas and for periodically updating the 1 1 million collected soundings sheets in their area of responsibility Individual Hydrographic Offices were charged with ensuring the regular supply of bathymetric data to the appropriate VHO and the IHB in Monaco maintained a co ordinating role in this scheme issuing information on the status of the various sheets from time to time Copies of the soundings sheets were available to the user community on direct application to the appropriate VHO a nominal charge was usually made to cover the cost of copying When the ICSU World Data Centre WDC system was established following the International Geophysical Year in the late 1950s the IHO became recognised as the World Data Centre for Bathymetry The Ocean Plotting Sheets formed the base from which much of the contouring of the GEBCO 5th Edition was compiled However during the preparation of the 5th Edition in the early 1980
156. million or better the exact scale being dependent on the density of data and the roughness of the topography The resulting contours were smoothed by hand and manually digitised After a careful edgematching of the various sheets the digital data set was then submitted to BODC for incorporating into the GEBCO Digital Atlas The digital trackline control information was generated automatically from the soundings database maintained within the AWI s mapping system PREPARATION OF AREA B Chief Editor H W Schenke G B Udintsev D E Teterin Scientific Compilation G B Udintsev D E Teterin G V Agapova S Barthel The sheet was extended into Area B in the framework of a joint German Russian collaboration between AWI and the V I Vernadsky Institute for Geochemistry and Analytical Chemistry Moscow In addition to the multibeam data collected by RV Polarstern the compilation benefited from extensive multibeam surveying by RV Akademic Boris Petrov Bathymetric contouring was based on a newly established data base comprising all existing single and multi beam data In data sparse areas the method of morphological interpolation was utilized and additional information from satellite radar altimetry gravity anomalies was included The initial computer contouring was made from a DTM at scales of 1 400 000 and 1 800 000 in 100 m contour line intervals This was followed by a manual interpretative editing of the seafloor topography utilizing the mor
157. mputing techniques at NGDC has revolutionised user access to the worldwide collection of echo sounding data A major step forward was taken in March 1993 when NGDC released a two volume CD ROM version of its complete GEODAS data holding It contained all data assimilated up to the end of 1992 and was accompanied by a user friendly software interface providing the user with direct access to over 4 gigabytes of marine geophysical trackline data including the complete holding of single beam echo sounding data Following the success of the CD ROM publication NGDC released updated versions of the CD ROM on an almost annual basis up to the end of 1998 thus ensuring that users were kept up to date with the holdings of the GEODAS database Thereafter NGDC adopted the methodology of posting updated data on the Internet as soon as they were assimilated into GEODAS thereby greatly minimising any delay in making newly submitted data including the echo sounding data submitted to the IHO DCDB available to users In June 2002 a new release of the GEODAS CD ROM was issued including all updates assimilated up to the end of May 2002 This latest release Version 4 1 now occupies three CD ROMs and offers over 7 gigabytes of marine geophysical trackline data With each succeeding release the software interface to the data has been enhanced and now provides the user with a powerful set of tools for selecting and plotting the data It also provides the users with a s
158. n Caribbean Areas U S Geological Survey Miscellaneous Investigations Series I 1864 A B Additionally tectonic sketches by Kathryn Scanlon based on GLORIA II imagery in Masson D G and Scanlon K M 1991 The neotectonic setting of Puerto Rico Geological Society of America Bulletin v 103 p 144 154 were used to interpret bathymetric contours Other reference information used in compilation was derived from the following publications Case J E and Holcombe T L 1980 Geologic tectonic map of the Caribbean Region U S Geological Survey Miscellaneous Investigations Series map no I 1100 Forsthoff G M and Holcombe T L 1987 Quaternary turbidities of the Muertos Trough northeastern Caribbean Sea composition source and dispersal patterns in Transactions of the Tenth Caribbean Geological Conference Cartagena p 353 367 McCann W R and Sykes L R 1984 Subduction of aseismic ridges beneath the Caribbean Plate implications for the seismic potential of the northeastern Caribbean Journal of Geophysical Research v 89 p 4493 4519 Ewing M Lonardi A G and Ewing J I 1965 The sediments and topography of the Puerto Rico Trench and Outer Ridge in Transactions of the Fourth Caribbean Geological Congress Trinidad p 325 334 Tucholke B E and Ewing J l 1974 Bathymetry and sediment geometry of the Greater Antilles Outer Ridge and vicinity Bulletin of the Geological Society of America v 85 p 1789 1802
159. n basins The polar regions were covered by 2 sheets only as opposed to 8 in the earlier editions These were on Polar Stereographic projection at a scale of 1 6 million at 75 latitude and reached to 64 N and S thus having a considerable overlap with the Mercator sheets A full list of the Scientific Co ordinators responsible for each sheet is given in Table 1 The land topography and coastlines for the Fifth Edition were taken from the Carte G n rale du Monde by permission of the Institut G ographique National Paris France The Antarctic continent was taken from maps supplied by the Scott Polar Research Institute in Cambridge England while the Arctic shoreline was taken from the American Geographical Society Map of the Arctic Region Each of the sheets depicted contoured bathymetry at standard depths of 200m 500m and at 500m intervals thereafter although the actual contours displayed varied slightly as some sheets also included contours at depths intermediate to the standard levels So as to ensure the standardization and general acceptance of the geographical names and the nomenclature used for ocean bottom features in the Fifth Edition each sheet was carefully scrutinised by the GEBCO Sub Committee on Geographical Names and Nomenclature of Ocean Bottom Features In conformance with the system used by the IHO for its International Nautical Chart series national versions of geographic names were used for land features transliterat
160. n data or of the GEODAS trackline inventory Any material reproduced from the GEBCO Digital Atlas should be accompanied by appropriate attribution to the source of the material For non GEBCO material such as the Coastline of Antarctica acknowledgement should include reference to the original source the ICSU Scientific Committee on Antarctic Research If the GEBCO bathymetry is being downgraded or is being reproduced over a large area covering many sheets then the source should be acknowledged as The GEBCO Digital Atlas published by the British Oceanographic Data Centre on behalf of IOC and IHO 2003 If the bathymetry is being reproduced in its original form for a specific region then the acknowledgement should include reference to the scientific co ordinators responsible for compiling the original contours for example The bathymetry is reproduced from GEBCO Sheet G 08 compiled by R L Fisher of the Scripps Institution of Oceanography and extracted from the GEBCO Digital Atlas published by the British Oceanographic Data Centre on behalf of the IOC and IHO 2003 Correct citation for this publication IOC IHO and BODC 2003 Centenary Edition of the GEBCO Digital Atlas published on CD ROM on behalf of the Intergovernmental Oceanographic Commission and the International Hydrographic Organization as part of the General Bathymetric Chart of the Oceans British Oceanographic Data Centre Liverpool DISCLAIMER Information in th
161. n disc 1 in netCDF format both for user selected display export via the GDA Software Interface and for direct access by the user c a five minute version of the GEBCO One Minute Bathymetric Grid Not accessible via the GDA Software Interface a stand alone version is stored on disc 2 for direct access by the user d the digitised bathymetric contours and coastlines from the First Edition of the International Bathymetric Chart of the Mediterranean A binary version is stored on disc 1 for user selected display export via the GDA Software Interface while an ASCII version is stored on disc 2 for users requiring direct access e a set of digital global coastlines from the World Vector Shoreline at a range of scales from 1 43 million up to 1 250 000 or better for coastlines north of 60 S A binary version is stored on disc 1 for user selected display export via the GDA Software Interface a direct access version is not available to the user f four versions of the SCAR Coastline of Antarctica Version 3 0 at a range of scales from 1 10 million up to 1 250 000 replacing the World Vector Shoreline south of 60 S A binary version is stored on disc 1 for user selected display export via the GDA Software Interface while an ASCII version is stored on disc 2 for users requiring direct access Page 10 of 141 g atrackline inventory of the digital echo sounding data held at the IHO Data Centre for Digital Bathymetry as of June 2002 A binar
162. n of the GDA contours as contained in the Centenary Edition but with supplementary data for a number of shallow water areas and semi enclosed seas Additional control contours and sounding data were used in some areas to constrain the gridding process It must be stressed that although the GEBCO grid is presented at one minute intervals of latitude and longitude so as to replicate the GEBCO contours this does not imply that knowledge is available on seafloor depth at this resolution indeed the depth in most one minute squares of the world s oceans has yet to be measured The GEBCO One Minute Grid is presented in the Centenary Edition of the GDA on disc 1 as one global netCDF data file In this form it is therefore directly available to UNIX users Alternatively users may prefer to visualise export user selected areas of the grid through the GDA Software Interface Users are referred to the User Guide to the GEBCO One Minute for a full account of the development of the grid the methods used to generate the grid the quality and limitations of the grid and the format and compatibility of the grid The User Guide was prepared by the GEBCO gridding team and includes an Appendix detailing the problems of generating a grid from the GEBCO contours The Centenary Edition of the GDA also includes a five minute global version of the GEBCO grid It was derived from the one minute grid by Walter Smith at the NOAA Laboratory for Satellite Altimetr
163. nary Edition of the GEBCO Digital Atlas White areas show sheets compiled at scales of better than 1 10 million Most of the update sheets G 01 to G 09 and IBCM were compiled primarily at scales of the order of 1 1 million Revised sheet 5 12 was compiled at 1 5 million and issued in 1994 Page II of 141 3 0 DATA SETS INCLUDED IN THE CENTENARY EDITION 3 1 GEBCO Contours and Trackline Control As mentioned the source material for the First Release of the GDA was obtained by digitizing the bathymetric contours coastlines and tracklines from the 18 sheets of the printed version of the Fifth Edition of GEBCO as published by the Canadian Hydrographic Service The series comprises 16 sheets on Mercator projection at a scale of 1 10 million at the equator in the region 72 S to 72 N and two polar sheets on polar stereographic projection at a scale of 1 6 million at 75 latitude The geographic coverage of the individual sheets used in the preparation of the First Release is shown in fig 1 It should be noted that whereas most of the Fifth Edition sheets were published between 1978 and 1982 a revised version of Sheet 5 12 see Annex L 12 was published in 1994 and a pre publication copy of this sheet was digitized for inclusion in the First Release of the GDA using material compiled at a scale of 1 5 million The preparation of Sheet 5 12 represented the first example of the use of digital techniques for updating the GEBCO This approach is no
164. national 1924 Hayford 72 00 S 160 00 W 46 40 S 062 00 W Bureau Gravimetrique International Toulouse France in collaboration with Institut Geographique National Paris France and the British Oceanographic Data Centre as for published chart but with an eastern limit of 78 W The digitized contours for the region 62 to 78 W may be found in the digitized version of GEBCO Sheet 5 16 bathymetric depth in corrected metres 0 200 500 1000m and at 500m intervals thereafter down to 5500m plus additional contours at 100m intervals between 2800m and 5300m in the following areas i North of 52 S 78 to 140 W ii North of 60 S 78 and 108 W iii 58 to 65 S 106 to 118 W DATA SOURCES USED IN THE COMPILATION OF SHEET 5 15 CONTOURS Mammerickx J Chase T E Smith S M and Taylor I L 1973 1974 Bathymetry of the South Pacific M R Technical Reports 51A 52A 53A amp 54A Molnar P Atwater T Mammerickx J and Smith S M 1975 Magnetic Anomalies Bathymetry and the Tectonic Evolution of the South Pacific since the Late Cretaceous Geophys J R Soc 40 383 420 Page 34 of 141 Cande S C Herron E M and Hall B R 1981 The Early Cenozoic Tectonic History of the Southeast Pacific Journal of Geophys Research in press The bathymetry east of longitude 78 W was taken from GEBCO sheet 5 16 and the bathymetry south of latitude 65 S was taken from GEBCO sheet 5 18 Page 135 of 141
165. nding survey in the late 1960s consisting of a series of east west tracks spaced less than 10km apart throughout the area Recontoured at intervals of 100m corrected onto 1 1 million scale compilation sheets maintained at the Institute of Oceanographic Sciences Wormley UK and later digitised for inclusion in GEBCO Sheet 97 3 The tracklines were not included on the original chart the sounding data east of 20 W were later published on CD ROM by the US National Geophysical Data Center Boulder and the relevant tracklines have been extracted from the CD ROM for inclusion in GEBCO Sheet 97 3 References Johnson G L Vogt P R amp Schneider E D 1971 Morphology of the Northeastern Atlantic and Labrador Sea Deutsche Hydrographische Zeitschrift 24 2 p 49 73 Johnson G L amp Schneider E D 1969 Depositional ridges in the North Atlantic Earth amp Planetary Science Letters 6 6 p 416 422 AREA 97 3 05 ICELAND FAROE RISE Extracted from Faroes Iceland Ridge Topographic Map Ed K Vollbrecht produced in 1973 by the Deutsches Hydrographisches Institut at a scale of 1 500 000 on Mercator projection Based on a detailed survey Contoured at intervals of 100m corrected but sometimes at intervals of 20m and occasionally at 10m intervals The 100m interval contours and trackline control were transcribed onto 1 1 million compilation sheets maintained at the Institute of Oceanographic Sciences Wormley UK Later digitised for in
166. ne feature types and sounding points as point feature types Line and point feature types are exported to separate files The Shapefile consists of a main file an index file and a dBASE table When the user enters a file name through the GDA Software Interface three files will be created For example if the data are to be saved with the name area1 shp files area1 shx index file and area1 dbf dBASE file will also be created A further set of three files area1Soundings dbf area1Soundings shp and area1Soundings shx will be created should the exported data include point features i e positions of sounding points If the exported data consists of only point features then the chosen name is used Page 25 of 141 ANNEX A Historical Background to GEBCO First Edition GEBCO was initiated at the turn of the century by HSH Prince Albert of Monaco It traces its origins to discussions held during the Seventh International Geographic Congress in Berlin in 1899 which resulted in a Commission being set up to study the naming of ocean relief features and to draw up plans for a general chart of the oceans The Commission was composed of ten leading geographers and scientists of the day HSH Prince Albert of Monaco Professor O Krummel Admiral S O Makarow Dr H R Mill Sir John Murray Dr Fridtjof Nansen Professor O Petersson Baron Richtofen Professor A Supan and Professor J Thoulet The Commission met in
167. nho M and Wannesson J 1986 The structure of the Guinean continental margin implications for the connection between the Central and South Atlantic Oceans Geologische Rundschau 75 57 70 Mascle J Blarez E and Marinho M 1988 The shallow structures of the Guinea and Ivory Coast Ghana transform margins their bearing on the Equatorial Atlantic Mesozoic evolution Tectonophysics 155 193 209 Mascle J Auroux C and the shipboard scientific team 1989 Les marges continentales transformantes ouest africaines Guinee Cote d lvoire Ghana et la zone de fracture de la Romanche Campagne Equamarge II fevrier mars 1988 Campagnes Oceanographiques Francaises Publications IFREMER 8 150 p Mascle J Equanaute 1994 Les marges continentales transformantes ouest africaines Cote d lvoire Ghana Guinee IFREMER Serie Reperes Ocean 5 125 p Mascle J Guiraud M Benkhelil J Basile C Bouillin J P Mascle G Cousin M Durand M Dejax J and Moullade M 1998 A geological field trip to the Cote d Ivoire Ghana transform margin Oceanologica Acta 21 1 1 20 Mascle J Guiraud M Basile C Benkhelil J Bouillin J P Cousin M and Mascle G 1993 La marge transformante de Cote d lvoire Ghana premiers resultats de la campagne Equanaute juin 1992 C R Acad Sci Paris 316 serie II 1255 1261 National Ocean Sediment coring Program National Science Foundation Initial Reports of th
168. ning colours to them A cursor controlled querying facility is available for displaying the value of any displayed contour The user is offered a choice of coastlines for display on the map either the coastline used in the chart series GEBCO or IBCM or the World Vector Shoreline SCAR coastline of Antarctica south of 60 S When accessing the GEBCO series the map can be overlaid with trackline control information ship s tracks isolated sounding points and survey boxes indicating the data used in the compilation of the GEBCO contours A cursor initiated query within any Page 19 of 141 survey box present in the viewing area will result in the details of the survey being displayed on the screen Alternatively the display can be overlaid with tracklines indicating the echo sounding data available from the IHO Data Centre for Digital Bathymetry as of June 2002 It should be noted that not all of these data were necessarily available when the GEBCO contours were compiled The display area can also be overlaid with symbols showing the locations of undersea features oceanic islands ports cities and Antarctic islands and stations A cursor controlled querying facility is available for displaying the names and supporting documentation in the case of undersea features of these features on the screen A geographic graticule can be overlaid for reference on the display area The geographic coordinates depth or elevation and e
169. nography GLOMAR CHALLENGER 1975 Texas A amp M University JOIDES RESOLUTION 1986 US Geological Survey 1971 Woods Hole Oceanographic Institute CHAIN 1961 to 1973 ATLANTIS II 1973 SHOM Mission Hydrographique de la cote Ouest d Afrique MHCOA LEON COURSIN 1958 to 1960 chasseur P699 1960 et BEAUTEMPS BEAUPRE Page 83 of 141 CHARTS CONSULTED Bathymetrie Carte Bathymetrique ERAP IFP COTE D IVOIRE Mission REINE POKOU Juin 1968 Ech 1 1 000 000 VALERY Bathymetric Map of the West African Continental Margin Dakar Monrovia April 1978 E J W Jones and C F Stuart Department of Geology University College London England West Africa Senegal and the Gambia Bathymetry Canadian Hydrographic Service Ottawa Canada 1977 Sierra Leone Guinee amp Guine Bissau West Africa Offshore free air gravity anomaly map E J W Jones amp C C S Mgbatogu University College London England 1979 Sierra Leone Guinee amp Guine Bissau West Africa Offshore total field magnetic anomaly map E J W Jones amp C C S Mgbatogu University College London England 1979 Monti S and Mercier H 1991 Romanche fracture zone Scale 1 1 000 000 Publication IFREMER Gravimetrie Anomalies a l air libre pour IBCEA d apres le modele Smith W H F amp Sandwell D T J G R 99 1997 SHOM PARIS FRANCE 1997 1998 Topographie pour IBCEA predite a partir de d
170. ns at 1 1 000 000 scale University of Utrecht The Netherlands Published as Collette B J and Roest W R 1992 Further investigations of the North Atlantic between 10 and 40 N and an analysis of spreading from 111 Ma ago to present Proceedings of the Koninklijk Nederlandse Akademie van Wetenschappen 95 2 159 206 amp 5 charts The following were widely consulted Hunter P M Searle R C and Laughton A S 1983 Bathymetry of the Northeast Atlantic Sheet 5 Continental Margin Off West Africa Scale 1 2 400 000 Admiralty Chart C6570 Hydrographer of the Navy Taunton U K Hunter P M Searle R C and Laughton A S 1986 Bathymetry of the Northeast Atlantic Sheet 4 Mid Atlantic Ridge to the Canary Basin Scale 1 2 400 000 Unpublished chart Institute of Oceanographic Sciences Wormley U K Global 2 min grid of Measured and Estimated Seafloor Topography Smith W H F and D T Sandwell 1997 Global Seafloor Topography from Satellite Altimetry and Ship Depth Soundings Science v 277 p 1956 1962 Detailed surveys were included from the following sources Page 79 of 141 N O Jean Chartcot Campagne Transwal 1979 Unpublished multibeam contours IFREMER Brest France Gridded Bathymetry on the Mid Atlantic Ridge RIDGE Multibeam Synthesis Project L DEO Columbia University U S A COMPILATION OF IBCEA SHEET 1 06 The compilation and digitization of the bathymetric contours for IBCEA Sheet 1 06 wa
171. ntarctic Research Expeditions 1980 1987 Data Reports 76 to 149 Kobarg W 1988 The tide dependent dynamics of the Ekstroem Ice Shelf Antarctica Ber Pol forschung 50 Pozdeyev V S and Kurinin R G 1987 New data on the morphology of the ice cover and relief of the subglacial bed and seabed bottom in the southern part of the Weddell Sea basin In Antarktika Doklady Komissii 26 p 66 71 English translation 1987 Robin G de Q 1958 Seismic shooting and related investigations Norwegian British Swedish Antarctic Expedition 1949 52 Scientific Results Vol V Glaciology III NPI Oslo Vaughan D G Sievers J Doake C S M Hinze H Mantripp D R Pozdeev V S Sandhager H Schenke H W Solheim A and Thyssen F 1994 Subglacial and Seabed Topography Ice Thickness and Water Column Thickness in the Vicinity of Filchner Ronne Schelfeis Polarforschung 64 2 p 75 88 Page 92 of 141 DATA SOURCES USED FOR GEBCO SHEET G 07 Area B Source Data The singlemost extensive source of data for compiling Area B bathymetry was provided by the cruises of RV Akademic Boris Petrov and RV Polarstern Alfred Wegener Institute for Polar and Marine Research Germany RV Polarstern Antarctic expeditions since 1983 Multibeam data from SeaBeam and Hydrosweep system single beam data from navigation echo sounder narrow beam echo sounder and Parasound sediment echo sounder Multibeam surveys by Hans Werner Schenke Fred
172. nto ten degree squares points were generated at the boundary of the squares for vectors crossing the ten degree boundaries If required the user can request that the vector segments are joined up on export providing they are first ordered as described above Page 23 of 141 TABLE 3 GDA Feature Codes for Vector Data The following integer based feature coding system is used for labelling GDA vector streams 0 for coastlines 1 for landward limit of seawater Antarctic coastline 2 for seaward limit of floating permanent ice Antarctic coastline depth in corrected metres for bathymetric contours 22010 for ice coastline definite 22011 for rock coastline definite 22012 for grounding line definite 22013 for rock against ice shelf definite 22020 for ice coastline approximate 22021 for rock coastline approximate 22022 for grounding line approximate 22023 for rock against ice shelf approximate 22030 for iceberg tongue 22040 for floating glacier tongue 22050 for ice shelf front 22090 for ice rumples distinct 22100 for ice rumples indistinct 22222 for tracklines 22223 for outlines of survey boxes special compilations or areas of dense sounding coverage 22224 for sounding points Note codes 1 2 and 22010 to 22100 correspond to Antarctic related coastlines ASCII files stored on the CD ROM do not use codes 1 and 2 these
173. ntours Present Comments David Monahan Canadian Hydrographic Service Ottawa Canada Robin H K Falconer New Zealand Oceanographic Institute Wellington New Zealand and Marie Tharp Lamont Doherty Geological Observatory Columbia University Palisades New York USA Geoscience Mapping Unit Canadian Hydrographic Service GEBCO SHEET 5 10 March 1982 1 to 10 million at the Equator International 1924 Hayford 46 40 S 110 00 E 00 00 S 160 00 W NERC Unit for Thematic Information Systems Reading UK in collaboration with the British Oceanographic Data Centre as for published chart bathymetric depth in corrected metres Om 200m 500m and at 500m intervals thereafter down to 10500m However for many areas intermediate contours are also included and the digital data set will be found to include contours at the following depths 50m 100m 300m 400m 4600m 4800m and at 100m intervals thereafter down to 5900m The digitized data for this chart were edgematched with that for GEBCO sheets 5 06 5 07 5 11 and 5 14 with the result that some of the contours at the sheet boundaries may be displaced slightly from their positions on the published chart As the digital data for GEBCO sheet 5 06 were supplied from a regularly updated data base and not digitized from the original sheet it proved difficult to achieve an edgematch with Page 123 of 141 the digital data for GEBCO sheet 5 10 most noticeably in the following
174. ntrol was submitted in digital form expressed as sounding points for both single and multibeam data Edgematching of the contours to surrounding areas in the GEBCO Digital Atlas was carried out at BODC SOURCES OF BATHYMETRIC SOUNDINGS ALONG TRACKLINES Bundesamt fuer Seeschiffahrt und Hydrographie Hamburg Rostock Canadian Hydrographic Service Ottawa U S National Imagery and Mapping Agency NIMA Silver Spring Maryland Head Department of Navigation and Oceanography St Petersburg South African Naval Hydrographic Office Cape Town Dienst der Hydrografie Koninklijke Marine Gravenhage UK Hydrographic Service Taunton International Hydrographic Bureau Monaco Instituto Hidrografico Lisboa Instituto Hidrografico de la Marina Cadiz National Geophysical Data Center Boulder Colorado National Ocean Service Silver Spring Maryland Service Hydrographique et Oceanographique de la Marine Paris SOURCES OF DETAILED BATHYMETRIC SURVEYS Bureau Gravimetrique International Institut National des Sciences de l Univers INSU Institut Francais de Recherche Scientifique pour le developpement en cooperation ORSTOM JEAN CHARCOT 1971 1979 Institut Francais de Recherche de Exploitation de la Mer IFREMER JEAN CHARCOT 1988 1990 SUROIT 1983 ATALANTE 1992 to 1995 Institute of Oceanographic Sciences IOS DISCOVERY 1983 Lamont Doherty Geological Observatory VEMA 1961 to 1973 CONRAD 1973 Scripps Institution of Ocea
175. o IBCCA International Bathymetric Chart of the Central Eastern Atlantic IBCEA International Bathymetric Chart of the Arctic Ocean IBCAO Page 3 of 141 Copyright and Attribution The contents and supporting software of the GEBCO Digital Atlas are copyright Reproduction in derivative form for scientific research environmental conservation education or other non commercial purposes is authorised without prior permission of the copyright holders providing the source material is properly credited Copying of the data in the GEBCO Digital Atlas in digital form for dissemination to third parties is prohibited without prior written permission from the British Oceanographic Data Centre The price of the GEBCO Digital Atlas has been deliberately set at a low level so as to encourage users to purchase their own copies Reproduction for resale or for use in a commercial product or for any other commercial purpose is prohibited without the prior written permission of the copyright holders In the first instance any request for such permission should be addressed to the British Oceanographic Data Centre email enquiries bodc ac uk and should include a clear statement of the purpose for which the material will be used and the manner in which it will be reproduced In the case of commercial activities consideration will always be given to the possibility of making an appropriate charge the benefits from which will be used for the further developmen
176. o 46 40 N were digitized at BODC from GEBCO sheet 5 06 published in April 1979 5 The 50m and 100m contours in the region 120 to 129 E 23 to 39 N i e the area of the East China Sea and Yellow Sea were absent in the digital data set supplied by JODC and were digitized by BODC from GEBCO sheet 5 06 Contour Units bathymetric depth in corrected metres Contours Present 0 200m 500m and at 500m intervals thereafter down to 10500m However in some areas the 50m and 100m contours are also included Comments As the digital data for the area 100 to 180 E 0 to 46 40 N were not digitized from GEBCO sheet 5 06 it proved difficult to achieve an accurate match at the boundaries with the surrounding GEBCO sheets This was due to variations in the track line control shown by the GEBCO sheets and in the paper atlas supplied by JODC This is most notable at 1 2 3 4 5 6 169 to 175 E 46 to 47 N i e the area of the Emperor Seamount Chain 150 to 151 E 0 N 135 to 139 E 0 N 9 30 to 10 N 180 E 34 30 to 35 30 N 180 E 41 30 to 43 N 180 E Page 14 of 141 ANNEX L 7 GEBCO Sheet 5 07 MINOR UPDATE NOTE The bathymetry of the area of GEBCO sheet 5 07 north of 15 N and east of 101 W has been replaced by the revised bathymetry contained in GEBCO Sheet G 03 GEBCO sheet 5 07 was published in March 1982 by the Canadian Hydrographic Service under the authority of the IHO and IOC
177. of grid line registered elevation in metres with negative values for bathymetric depth and positive values for topographic heights Details on the formatting may be found in the readme file of the GRIDFIVE Directory Page 22 of 141 TABLE 2 Simple ASCII Format for GDA Vector Data Note this format has been modified slightly since the 1994 and 1997 releases of the GDA with the inclusion of a flag character IFLAG to mark a header record Within this format files are built up as a series of labelled vector streams relating to bathymetric contours coastlines tracklines survey box outlines or sounding points A new vector stream is started for each contour segment coastline segment trackline survey box outline or sounding point Each vector stream consists of coordinate pair records preceded by a header record containing a flag character set to gt a feature code ICODE as in Table 3 for the vector and a count ICOUNT of the number of succeeding coordinate pairs making up the vector Each co ordinate pair is stored in a record with a geographic latitude ALAT and longitude ALONG each expressed in decimal degrees Each record is made up of 20 bytes as follows Header record IFLAG ICODE ICOUNT in format A1 216 5X CR LF Co ordinate pair record ALAT ALONG in format F8 4 F10 4 CR LF In the CD ROM ASCII files latitude is stored in the range 90 to 90 with north positive and south negative and
178. ographic Department In 1982 the XIIth International Hydrographic Conference at Monaco adopted the Third Edition Tables to replace Matthews Tables Second Edition The Third Edition Tables are applicable for use throughout the world in water depths greater than 200 metres and cover depth to the sea bed in each of 85 echo sounding areas The tables are in metres and cater for echo sounders calibrated to 1500 m s a conversion table for 1463 m s being provided As the boundaries between echo sounding correction areas lie along exact degrees of latitude and longitude the tables are particularly suited for computerised use The Centenary Edition of the GDA Directory CARTER on disc 1 contains a directly accessible set of files to enable the user to set up his own system for computing the echo sounding correction according to the Third Edition Tables given the ship position and the uncorrected depth reading The files include the echo sounding correction area definitions and correction tables together with the necessary computer routines and documentation for installing the system In addition the GDA Software Interface also provides a facility for automatically computing the echo sounding correction at the geographic position of the cursor on the user s display screen the user simply supplies the uncorrected depth reading and the system returns the echo sounding correction area identifier and the corrected depth value or vice versa Page 50 o
179. ogt M F Czarnecki Y Kristoffersen A Midthassel and K Rokoengen 1991 Bathymetry of the Barents and Kara Seas Geological Society of America Map and Chart Series MCH047 scale 1 2 313 000 1 sheet Head Department of Navigation and Oceanography All Russian Research Institute for Geology and Mineral Resources of the World Ocean and Russian Academy of Sciences 1999 Bottom relief of the Arctic Ocean Head Department of Navigation and Oceanography St Petersburg map scale 1 5 000 000 1 sheet Head Department of Navigation and Oceanography 1989 1998 Hydrographic Charts 11139 11140 11142 11143 11150 11152 11155 12230 12334 12335 12344 12348 12401 12404 12407 12417 12428 12433 13317 13410 13420 13421 13425 13426 13432 14305 14321 14403 14404 14411 14420 14421 14427 14433 14434 15430 16442 18330 19448 19453 698 948 955 scales from 1 10 000 to 1 700 000 Matishov G G N Z Cherkis M S Vermillion and S L Forman 1995 Bathymetry of the Franz Josef Land Area Geological Society of America Map and Chart Series MCHO80 scale 1 500 000 1 sheet Perry R K H S Fleming J R Weber Y Kristoffersen J K Hall A Grantz G L Johnson N Z Cherkis and B Larsen 1986 Bathymetry of the Arctic Ocean Geological Society of America Map and Chart Series MC 56 scale 1 4 704 075 1 sheet Siefert T and B Kayser 1995 A high resolution spherical grid topography of the Baltic Sea Meeresw
180. ompilations G 01 Arctic Ocean see Annex K 1 The contours for this region were compiled in 2001 from the gridded data set of the IBCAO and were prepared for GEBCO by Norman Cherkis formerly of the Naval Research Laboratory Washington and Martin Jakobsson University of New Hampshire Durham G 02 North east Atlantic off the British Isles see Annex K 2 Compiled in February 1997 and originally published as sheet 97 3 in the 1997 release of the GEBCO Digital Atlas This sheet was assembled by Peter M Hunter Southampton Oceanography Centre U K from bathymetric charts compiled at the Institute of Oceanographic Sciences Wormley Surrey U K G 03 Caribbean Sea and the Gulf of Mexico see Annex K 3 Two sets of updated bathymetry were submitted to GEBCO for this region a IBCCA Sheets 1 01 to 1 04 prepared by the National Geophysical Data Center Boulder for the Northern Gulf of Mexico and the Atlantic Ocean east of Florida Page 12 of 141 b IBCCA Sheets 1 05 to 1 09 for the Southern Gulf of Mexico and the northern part of the Caribbean from Jos Frias Salazar at the Instituto Nacional de Estadistica Geografia e Informatica INEGI in Mexico G 04 North east Atlantic off the Iberian Peninsula see Annex K 4 This sheet is a composite of three bathymetric compilations a Bathymetric Chart of the Bay of Biscay published in 1994 and compiled by IFREMER Centre de Brest France b IBCEA Sheet 1 01 published in February 20
181. on It does not imply that all seafloor features within the area of the sheet are mapped to that scale The resolution or even presence of features is dependent on the density of sounding coverage and this is usually highly variable indeed there are often large gaps between tracks The Centenary Edition of the GDA includes all bathymetric contours assimilated into the GDA up to October 2002 together with the associated coastlines and trackline control This data set appears in two forms one tailored for user selected display export through the GDA Software Interface while the other is available as a set of standalone ASCII files directly accessible by the user The contours and coastlines of the IBCM are also available in both forms 3 2 The GEBCO One Minute Grid Users are referred to the User Guide to the GEBCO One Minute Grid for a full account of the development and limitations of the grid and are strongly advised to read it before making use of the grid Since the early 1990s the GEBCO community has clearly recognized the importance of generating a gridded version of GEBCO on a uniform global grid With modern computing technology the gridded format offers far more flexibility than traditional contour vectors particularly in modelling applications and in the visualisation and manipulation of data The generation of a uniform bathymetric grid of the seafloor is not a simple problem as the distribution of available sounding data i
182. onnees altrimetriques et bathymetriques Modele Smith W H F amp Sandwell D T J G R 99 1994 SHOM PARIS FRANCE 1997 BIBLIOGRAPHY Allen J R L 1964 The Nigerian continental margin bottom sediments submarine morphology and geological evolution Marine Geology 1 289 332 Allen P M 1969 The geology of part of an orogenic belt in western Sierra Leone West Africa Geol Rund 58 588 620 Arens G Delteil J R Valery P Damotte B Montadert L and Patriat P 1971 The continental margin off the Ivory Coast and Ghana In F M Delany Ed The Geology of the East Atlantic Continental Margin Vol 4 Africa ICSU SCOR Working Party 31 Symp Cambridge Rep No 70 16 Inst Geol Sci London 64 78 Andrews Jones D A 1971 Structural history of Sierra Leone In Tectonics of Africa UNESCO Paris 205 7 Baker C O and Bott M H P 1961 A gravity survey over the Freetown basic complex of Sierra Leone Overseas Geol Min resources 8 260 78 Basile C Mascle J Auroux C Bouillin J P Mascle G Goncalvez De Souza K et le groupe Equamarge 1989 Une marge transformante type la marge continentale de Cote d Ivoire Ghana resultats preliminaires de la campagne Equamarge II mars 1988 C R Acad Sci Paris 308 serie 11 997 1004 Page 84 of 141 Basile C Brun J P and Mascle J 1992 Structure et formation de la marge transformante de Cote d Ilvoire Ghana apports de l
183. ontinent Boundaries p 265 289 Kluwer Academic Publisher Page 94 of 141 ANNEX K 8 GEBCO Sheet G 08 Greater Indian Ocean BATHYMETRY OF THE GREATER INDIAN OCEAN compiled September 2002 Note a subset of this sheet was released as GEBCO sheet 97 1 in the 1997 release of the GEBCO Digital Atlas covering the area of the Indian Ocean south of 31 S and extending from 10 W in the South Atlantic to 140 E south of Australia This area has been further updated and the sheet now extends to cover the whole of the Indian Ocean from Asia down to Antarctica extending eastwards to 170 E in the south west Pacific and westwards to 12 W in the south east Atlantic The area covered is about a quarter of the world s oceans Author Dr Robert L Fisher Scripps Institution of Oceanography La Jolla California USA Digitised by Pauline Weatherall British Oceanographic Data Centre Sheet Limits 31 N to 72 S 12 W to 170 E see below for detailed coverage Scale Contours compiled and digitised on Mercator sheets at a scale of 4 inches per degree longitude i e approximately 1 1 million Horizontal Datum WGS 84 Contour Units Bathymetric depth in corrected metres Contours present standard GEBCO depths i e 200m 500m and at 500m intervals thereafter down to 7000m Locally the 100m contour is also present Coastline Source SCAR Coastline of Antarctica south of 60 S Version 3 0 Full resolution version at a scale of 1 1 million or
184. orld the coastline is simply the boundary between the land and the sea However in the Antarctic the concept of a coastline is more complex and needs to represent the boundary between three domains viz land sea and ice shelf Furthermore the WVS is known to be suspect around Antarctica With the publication of the SCAR Antarctic Digital Database in 1993 see Annex E a high quality seamless and coherent coastline of Antarctica became available for the first time Not only is it in digital vector form but it also clearly codifies the different types of coastline and includes a far more comprehensive definition of ice shelf limits than has been available hitherto Compiled from a combination of existing maps and satellite imagery this new coastline is suitable for use at scales of up to 1 1 million With the kind agreement of SCAR it was decided to standardise the GEBCO coastline south of 60 S on the SCAR Coastline and to replace the WVS in this area with the SCAR Coastline As there are no coasts crossing the 60 S latitude which is the boundary between the two data sets there are no discontinuities of coastline For those areas where the bathymetry has not been updated since the GEBCO Fifth Edition the digital coastline included with the GDA bathymetry remains as portrayed on the GEBCO Fifth Edition sheets i e based at a scale of 1 10 million on the Carte G n rale du Monde or for the Antarctic continent on earlier maps provided by the Sc
185. ott Polar Research Institute in Cambridge England However as the bathymetry of each area is updated the coastline within the area is being replaced with the WVS and or the SCAR coastline as appropriate During the updating checks are made to ensure that the bathymetry and coastline are consistent e g the bathymetry does not cross the coastline It will be noted that the coastlines used with the update sheets G 01 to G 09 and also revised sheet 5 12 have been taken from the WVS and or SCAR data sets Although the WVS and SCAR coastlines are only merged in with the GEBCO bathymetry as and when the bathymetry is updated complete copies of these coastline data sets are available on the Centenary Edition of the GDA User selected extracts may be displayed exported through the GDA Software Interface In the case of the SCAR coastline a stand alone ASCII version is also available for direct access by the user The WVS is available at scales of 1 250 000 1 1 million 1 3 million 1 12 million and 1 43 million while the SCAR coastline is at scales of full resolution 1 1 million 1 5 million and 1 10 million Page l6 of 141 3 4 Geographic Names Included in Centenary Edition are geographically referenced lists of the names of undersea features ports and cities oceanic islands Antarctic islands and Antarctic stations This information see Annex G is available to the user via queryable feature symbols that can be overlain on the map area of char
186. ours coastlines and trackline control from the GEBCO Fifth Edition a digitized version of the International Bathymetric Chart of the Mediterranean IBCM a high resolution digital global coastline a digital gazetteer of undersea feature names and a trackline inventory of the echo sounding data held at the IHO Data Centre for Digital Bathymetry A Second Release was published by BODC in March 1997 which included new bathymetric charts for the southern Indian Ocean the Weddell Sea and the north east Atlantic off the British Isles and an improved coastline for Antarctica The uptake of the first two releases of the GDA has been highly successful and the CD ROM is in regular use in many research laboratories hydrographic offices commercial companies universities libraries data centres and government departments scattered across the globe By 2002 BODC had distributed some 1 320 copies to users in 87 countries worldwide The Centenary Edition of the GDA is being released to coincide with the hundredth anniversary of the offer made in April 1903 by HSH Prince Albert of Monaco to fund and organise the production of a series of charts to be called the General Bathymetric Chart of the Oceans The Centenary Edition includes completely new bathymetry for the Arctic and Indian Oceans as well as significant updates for areas of the North Atlantic the Weddell Sea and the area around New Zealand Indeed since the Fifth Edition was first digi
187. ours present Coastline Source Digitised by Hans Werner Schenke Alfred Wegener Institute for Polar and Marine Research Bremerhaven Germany and Gleb B Udintsev Vernadsky Institute of Geochemistry and Analytical Chemistry Moscow 60 S to 79 S 75 W to 2 E see below for detailed coverage Contours compiled and digitised on Mercator sheets at a variety of scales between 1 250 000 and 1 1 million WGS 84 bathymetric depth in uncorrected metres assuming a sound velocity in seawater of 1500m s see note below 100m intervals down to 7200m SCAR Coastline of Antarctica version 3 0 full resolution version at scale of 1 1 million and better Alfred Wegener Institute for Polar and Marine Research Bremerhaven Germany Geographic Coverage Published Charts 60 S to 66 S 75 W to 15 W 65 S to 66 S 15 W to 2 W 66 S to 79 S 75 W to 2 E Printed charts published by the Alfred Wegener Institute as a series of nine sheets 533 535 551 553 566 568 as part of the 1 1 million scale AWI Bathymetric Chart of the Weddell Sea Antarctica Sheets 533 535 published jointly with Vernadsky Institute of Geochemistry and Analytical Chemistry Coverage as follows 60 66 S 75 55 W 533 55 35 W 534 35 15 W 535 66 72 S 66 50 W 551 50 25 W 552 25 0 W 553 72 78 S 75 50 W 566 50 25 W 567 25 0 W 568 Note on contour units Prior to contouring for use in GEBC
188. overlays as required for legibility and clarity In contouring the standard GEBCO contour levels were followed i e 500m intervals plus the 200m contour and occasionally on wide shelves the 100m contour The contoured depths are in corrected metres using Carter s Tables NP 139 Echo Sounding Correction Tables 3rd Edition D J T Carter Hydrographic Department Taunton 1980 None of the contouring was taken from existing nautical or scientific publications or manuscripts rather all was done by hand from 1987 to 2002 by Dr Fisher from his collection of soundings sheets In constructing the contours the echo sounding based interpretation was compared with large scale portrayals of satellite altimetry topography Such gravity based portrayals were constructed from a data file available at SIO Sandwell D T and W H F Smith Marine Gravity Anomalies from GEOSAT and ERS 1 Altimetry version 7 2 Aug 1996 Journal of Geophysical Research vol 102 p 10 039 10 054 These comparisons at large scale helped eliminate spurious structural trends or major misconnections in regions contoured from sparse shipboard coverage However depth contour levels are based entirely on sounding data gravity indications affected only the general shape of features detectable from existing soundings The hand contoured sheets at a scale of 4 inches per degree longitude and their corresponding trackline plots were duplicated at SIO and sent to the British
189. phic Service Published chart GEBCO SHEET 5 01 April 1978 Projection Mercator Scale 1 to 10 million at the Equator Ellipsoid International 1924 Hayford Southern Limit 46 40 N Western Limit 000 00 E Northern Limit 72 00 N Eastern Limit 090 00 E Digitised by Bureau Gravimetrique International Toulouse France in collaboration with Institut Geographique National Paris France and the British Oceanographic Data Centre Geographic Area Digitized as for published chart Contour Units bathymetric depth in corrected metres Contours Present Om 50m 100m and at 100m intervals thereafter down to 3700m DATA SOURCES USED IN THE COMPILATION OF SHEET 5 01 CONTOURS Bathymetric contours are based on collected oceanic soundings up to 1975 from the German Hydrographic Office Hamburg and additional data contour maps and nautical charts from Norway USSR Sweden Germany UK and USA GEBCO Collected Soundings Sheets GEBCO Plotting Sheets 30 1972 and 17 1972 from UK Hydrographic Office GEBCO Plotting Sheets 10 1972 and 18 1972 from Swedish Hydrographic Office Page 103 of 141 GEBCO Plotting Sheets 9 1972 3 1972 4 1972 and 4A 1970 from German Hydrographic Office Nautical Charts Norwegian nautical charts No 301 INT 140 307 308 309 310 311 319 320 321 322 323 324 325 551 552 553 557 558 559 British nautical charts No 3180 3181 2963 2962 USSR nautical charts No 601 650
190. phological regularities and radar altimetry information The final contours were digitised by scanning and after vectorising included in a Geographic Information System GIS for the cartographic visualization and charting The contour lines were generalized smoothed and edited for the final scale of 1 1 million The digital data set was then submitted to BODC for incorporating into the GEBCO Digital Atlas together with digital trackline control information generated automatically from the soundings database DATA SOURCES USED FOR GEBCO SHEET G 07 Area A Although multi beam data from RV Polarstern provided the singlemost extensive source of data analogue and digital sounding data were also supplied by many other organisations for use in compiling Area A In particular the following Hydrographic Offices contributed data Servicio de Hidrografia Naval Buenos Aires Argentina Diretoria de Hidrografia e Navegacao Niteroi Brazil Hydrographic Department Tokyo Japan Statens Kartverk Stavanger Norway Hydrographic Office Cape Town South Africa Hydrographic Office Taunton UK Defense Mapping Agency Washington USA Head Department of Navigation amp Oceanography St Petersburg Russia The following scientific institutions or individuals supplied data Page 91 of 141 British Antarctic Survey Cambridge UK C Doake B Harrods Bureau Gravimetrique International Toulouse France Institute of Geophysics University of Texas
191. piling and interpreting these data into bathymetric charts their names are to be found in the chart descriptions presented in Annexes K and L On this occasion special acknowledgement is due to Mike Carron Bill Rankin Andrew Goodwillie Walter Smith Peter Hunter and the other contributors who assisted in generating the GEBCO One Minute Grid The generosity shown by the following organizations in making their products available for use in the GEBCO Digital Atlas is gratefully acknowledged ICSU Scientific Committee on Antarctic Research for the Coastline of Antarctica U S National Imaging and Mapping Agency for the World Vector Shoreline International Hydrographic Bureau for the IHO IOC Gazetteer of Geographic Names of Undersea Features UK Hydrographic Office for the Third Edition Echo Sounding Correction Tables U S National Geophysical Data Center for the GEODAS trackline inventory of echo sounding data held at the IHO Data Centre for Digital Bathymetry IGBP GLOBE Project for the land elevation data in the GEBCO One Minute Grid Alfred Wegener Institute for Polar and Marine Research for the Bathymetric Chart of the Weddell Sea New Zealand National Institute of Water and Atmospheric Research for the Bathymetric Chart of the New Zealand Region and the following IOC Regional Ocean Mapping Projects International Bathymetric Chart of the Mediterranean IBCM International Bathymetric Chart of the Caribbean Sea and Gulf of Mexic
192. plete data set of the digital contours coastlines and tracklines for the GEBCO Fifth Edition was finalised in June 1993 thereby providing a high quality digital base from which future editions of GEBCO might evolve Page 35 of 141 ANNEX D World Vector Shoreline WVS WVS was produced by the US National Imagery and Mapping Agency formerly the US Defense Mapping Agency and has been adopted as the standard world coastline for the updating of GEBCO north of 60 S Note south of 60 S the WVS has been replaced for GEBCO use by the SCAR Scientific Committee on Antarctic Research coastline of Antarctica Once the GEBCO Digital Atlas had been initialized by digitizing the published sheets of the GEBCO Fifth Edition the updating of GEBCO bathymetry was no longer constrained by scale It was anticipated that it could well be updated in certain regions at scales of up to 1 500 000 or even 1 250 000 in isolated cases However by its very nature the GEBCO Fifth Edition coastline based primarily on the Carte du Monde of the Institut Geographique National Paris was suited only for use at scales of the order of 1 10 million In 1989 a search was instigated by the GEBCO Sub Committee on Digital Bathymetry for an alternative coastline satisfying the criteria that it should be a digital b suitable for use at scales up to 1 250 000 c global in coverage and d of consistent accuracy across the globe It was fortunate that just at that time
193. poral and Spatial Variations of Accretionary Processes Marine Geophysical Researches 13 1 1 20 Page 130 of 141 ANNEX L 14 GEBCO Sheet 5 14 MAJOR UPDATE NOTE The bathymetry in the area of GEBCO sheet 5 14 west of 170 E and west of 167 W north of 57 5 S has been replaced by the revised bathymetry contained in GEBCO sheets G 08 and G 09 GEBCO Sheet 5 14 was published in November 1981 by the Canadian Hydrographic Service under the authority of the IHO and IOC Scientific Coordinators Cartography by Published Chart Projection Mercator Scale Ellipsoid Southern Limit Western Limit Northern Limit Eastern Limit Digitized by Geographic Area Digitized Contour Units Contours Present Robin K H Falconer supported by the Bedford Institute of Oceanography Dartmouth Canada and the New Zealand Oceanographic Institute Wellington New Zealand and Marie Tharp Lamont Doherty Geological Observatory New York U S A Geoscience Mapping Unit Canadian Hydrographic Service GEBCO SHEET 5 14 November 1981 1 to 10 million at the Equator International 1924 Hayford 72 00 S 110 00 E 46 40 S 160 00 W Bureau Gravimetrique International Toulouse France in collaboration with Institut Geographique National Paris France and the British Oceanographic Data Centre as for published chart bathymetric depth in corrected metres 0 200 500 1000m and at 500m intervals thereafter down to 6
194. posium University of Wisconsin Press Page 132 of 141 Molnar P Atwater T Mammerickx J and Smith S M 1977 Magnetic anomalies bathymetry and the tectonic evolution of the south Pacific since the late Cretaceous Geophys Journ Royal Astonom Soc 40 383 420 Vanney J R Falconer R K H and Johnson G L 1981 Geomorphology of the Ross Sea and adjacent oceanic provinces Marine Geol 41 73 102 Weissel J K and Hayes D E 1977 Evolution of the Tasman Sea reappraised Earth and Planetary Sci Letters 36 77 84 Weissel J K Hayes D E and Herron E M 1977 Plate tectonic synthesis the displacements between Australia New Zealand and Antarctica since the late Cretaceous Marine Geol 25 231 277 Page 133 of 141 ANNEX L 15 GEBCO Sheet 5 15 GEBCO Sheet 5 15 was published in March 1982 by the Canadian Hydrographic Service under the authority of the IHO and IOC Scientific Coordinators Cartography by Published Chart Projection Mercator Scale Ellipsoid Southern Limit Western Limit Northern Limit Eastern Limit Digitized by Geographic Area Digitized Contour Units Contours Present Jacqueline Mammerickx Isabel L Taylor Scripps Institution of Oceanography La Jolla U S A and Steve Cande Lamont Doherty Geological Observatory New York U S A Geoscience Mapping Unit Canadian Hydrographic Service GEBCO SHEET 5 15 March 1982 1 to 10 million at the Equator Inter
195. r through the help menu Useful help is provided to enable the new user to get started A brief overview of the main features of the GDA Software Interface is given below details concerning the export of data are given in section 5 A choice of map projections is available to display the data Equidistant Cylindrical Mercator Miller Cylindrical Lambert Cylindrical Equal Area and Polar Stereographic Initial geographic area selection is made by chart number by chart area by geographic latitude and longitude limits or by a user controlled zoom box This initially selected area becomes the basemap Within the initially selected basemap area the user can zoom in and out of their particular area of interest and pan across to adjacent areas as required Any export of data from the GDA will be based on the data in the area of the displayed map A coloured backdrop to the map can be generated from the GEBCO One Minute Grid with colour coding according to depth and elevation as selected by the user Cross section depth elevation profiles can be displayed for user specified sections across the map The profiles can be filled with colour coded according to depth and elevation Bathymetric contours can be displayed on the map from either the GEBCO chart series or in the case of the Mediterranean the IBCM First Edition Facilities are provided for selecting the depths of contours to be displayed on the map and for assig
196. re well versed in the problems of gridding and made extensive use of the widely used GMT package of software programs Initially the grid was to be produced at 2 5 minute intervals in geographic latitude and longitude but in early 2002 it was decided to create the grid at 1 minute intervals so as to better replicate the GDA contours and to establish a higher resolution base for future updating It would also interface better with high resolution global grids such as IGBP GLOBE In late 2002 the first version of the global grid was completed and made available for inclusion in the GDA The work was co ordinated by Michael Carron now at the NATO SACLANT Undersea Research Centre with major input provided by the gridding efforts of Bill Rankin and Lois Varnado at the US Naval Oceanographic Office Andrew Goodwillie at Scripps Institution of Oceanography and Peter Hunter at Southampton Oceanography Centre Significant regional contributions were also provided by Martin Jakobsson University of New Hampshire Ron Macnab Geological Survey of Canada Hans Werner Schenke Alfred Wegener Institute for Polar and Marine Research John Hall Geological Survey of Israel and lan Wright New Zealand National Institute of Water and Atmospheric Research Technical advice and support on algorithms was provided by Walter Smith The GEBCO One Minute Grid is fully global and includes land elevations from the IGBP GLOBE database It is based on the October 2002 versio
197. rgin off Western Africa Cape St Francis South Africa to Walvis Ridge Southwest Africa Bull Am Assoc Petr Geol 59 2 59 Forsyth D W 1975 Fault plane solutions and tectonics of the South Atlantic and Scotia Sea J Geophys Res 80 1429 1443 Griffiths D H and Barker P R 1972 Review of marine geophysical investigations in the Scotia Sea Adie R J Ed Antarctic Geology and Geophysics Universitetsforlaget Oslo 3 11 Harrington P K Barker P F and Griffiths D H 1972 Crustal structure of the South Orkney Islands area from seismic refraction and magnetic measurements Adie R J Ed Antarctic Geology and Geophysics Universitetsforlaget Oslow 27 32 Herron E M Cande S C and Hall B R An active spreading center collides with a subduction zone a geophysical survey of the Chile margin triple junction Submitted to the Nazca Plate volume Amer Geophys Union Herron E M Bruhn R Winslow M and Chuaqui L 1977 Post Miocene tectonics of the margins of southern Chile Talwani M Pitman W C III Eds Island Arcs Deep Sea Trenches and Back Arc Basins Maurice Ewing Series 1 Amer Geophys Union 273 284 Herron E M and Tucholke B E 1976 Sea floor magnetic patterns and basement structure in the southeastern Pacific Hollister C D Craddock C et al Page 138 of 141 ANNEX L 18 GEBCO Sheet 5 18 MAJOR UPDATE NOTE The bathymetry in the area of GEBCO sheet 5 18 between 0 W and
198. rty Geological Observatory Columbia University Palisades New York USA Page 127 of 141 National Geophysical and Solar Terrestrial Data Centre Washington D C USA Ocean Research Institute University of Tokyo Tokyo Japan School of Marine and Atmospheric Science University of Miami Miami Florida USA School of Oceanography Oregon State University Corvallis Oregon USA Scripps Institution of Oceanography University of California San Diego La Jolla California USA Shirshov Institute of Oceanology Academy of Science Moscow USSR Woods Hole Oceanographic Institution Woods Hole Massachusetts USA SCIENTIFIC LITERATURE Brodie J W Summerhayes C P and Kibblewhite A C 1966 1969 Bathymetry Island Chart Series AITUTAKI ATIU MANGAIA MANNUAE MANGAIA MAUKE RAROTONGA 1 200 000 New Zealand Oceanographic Institute Herron E 1978 Bathymetry of the Chile Rise Chile Trench triple junction unpublished manuscript Lonsdale P 1977 Regional shape and tectonics of the equatorial East Pacific Rise Marine Geophysical Researches 3 295 315 Lonsdale P and Klitgord K D 1978 Structure and tectonic history of the Eastern Panama Basin Geological Society of America Bulletin 89 981 999 Mammerickx J Anderson R N Menard H W and Smith S 1975 Morphology and tectonic evolution of the East Central Pacific Geological Society of America Bulletin 86 111 118 Monti S and Pautot G 1974
199. rveys conducted by the U S National Oceanic and Atmospheric Administration National Ocean Service Coast Survey Track spacing varies with depth 0 1 to 0 8 km track spacing for depths from 0 to 200 meters 0 8 to 1 6 km track spacing for depths from 200 to 900 meters 3 2 km track spacing for depths from 900 to 2750 meters 8 0 km track spacing for depths over 2750 meters Digital contours from the U S Geological Survey CONMAP data base derived from U S Coast Survey 1 250 000 scale bathymetric maps were used in some areas to fill in small data gaps 2 U S Naval Oceanographic Office bathymetric contour sheet 805 NA 9 scale 1 1 000 000 compiled by F H Sorenson in 1984 100 meter contour approximated 3 Surveys conducted by the U S Naval Oceanographic Office ships USS Sheldrake USS Prevail and USS Pursuit from 1959 to 1964 Trackline spacing from 0 3 to 1 8 km 4 Contours digitally generated from a three arc second gridded five beam subset of multibeam surveys conducted by the Scripps Institution of Oceanography ship ATLANTIS II in 1986 Imagery from the side scanning sonar system GLORIA II obtained by the U S Geological Survey was employed in the interpretation of bathymetric contours along portions of the Florida Escarpment IBCCA SHEET 1 04 Scientific Coordinator Troy L Holcombe MGG NGDC Compiler Lisa A Taylor MGG NGDC Sources of Bathymetric Data and Bathymetric Contours Numbers correspond to numbered areas
200. s In 1983 the bathymetric contours and coastlines depicted on the IBCM First Edition were digitised by a commercial company from polyester transparencies of the ten 1 1 million master sheets The digitisation was carried out by manual curve following on a digitising Page 53 of 141 table according to the specification that a ninety percent of the digitised points should fall within 0 3mm of their position on the source map with no point to exceed 1 0mm from that position and b the maximum distance between successive digitised points should be 1 0mm In 1988 a detailed review and editing of the digitised data was carried out by the British Oceanographic Data Centre on behalf of the IOC After removal of some minor digitising errors the review confirmed that in general the digitisation accuracy was within the line thickness 0 3mm of the plotted out digitised contours The standard of digitisation of the 1 2 million chart of the Black Sea was found to be slightly inferior to that of the other sheets although still within 1 chart mm All bathymetric contours and coastlines present on the published sheets are included in the digital data set where they are expressed in vector form in geographic coordinates The digitised data set does not include the land contours or the underlying track control information Page 54 of 141 ANNEX K Supporting Documentation for Bathymetric Charts used to update the GEBCO Digital Atlas This Annex
201. s carried out by SHOM Available sounding data from collected soundings sheets and single and multibeam surveys were assembled into a digital database with all data corrected according to Echo Sounding Correction Tables publication NP 139 2nd and 3rd editions Hydrographic Office United Kingdom The data were plotted onto 1 250 000 sheets where they were manually contoured at intervals of both 200m and 500m Geomorphological considerations were applied in the contouring and reference was made to satellite altimetry data existing charts and available books reports and archives The contours were then digitized and submitted to BODC for use in GEBCO the trackline control was submitted in digital form expressed as sounding points for both single and multibeam data IBCEA Sheet 1 06 Sources of soundings Bundesamt fur Seeschiffahrt und Hydrographie Hamburg Rostock Canadian Hydrographic Service Ottawa U S National Imagery and Mapping Agency NIMA Silver Spring Maryland Head Department of Navigation and Oceanography St Petersburg South African Naval Hydrographic Office Cape Town Dienst der Hydrografie Koninklijke Marine Gravenhage UK Hydrographic Service Taunton International Hydrographic Bureau Monaco Instituto Hidrografico Lisboa Instituto Hidrografico de la Marina Cadiz National Geophysical Data Center Boulder Colorado National Ocean Service Silver Spring Maryland Service Hydrographique et Oceanographique de l
202. s it became apparent that a number of the GEBCO scientists responsible for undertaking the contouring had at their disposal considerably more data than appeared on the 1 1 million sheets maintained by the VHOs The shortfall in data submission to the VHOs appeared closely related to the introduction of computer techniques for the handling of bathymetric data particularly in the geoscience community Since the late 1960s geoscientists had been finding it far more convenient to store and exchange their data in computer files and to plot out data automatically as and when the need arose Computer techniques also enabled far greater volumes and densities of echo sounding data to be handled than could be readily hand scribed onto plotting sheets The GEBCO Sub Committee on Digital Bathymetry SCDB reviewed this situation in 1986 recognising that a major part of the missing data might well be found in the underway marine geophysics database maintained by the US National Geophysical Data Center NGDC in Boulder At that time the Boulder centre held almost 2 000 cruises of bathymetric magnetic and gravity data primarily from US laboratories but also with contributions from Japan France Russia UK New Zealand Canada South Africa and China The database already included over seven million nautical miles of digital echo sounding data and had clearly demonstrated the practicality and value of computing techniques for managing such data The SCDB advis
203. s 54 73 84 91 Hydrographer of the Navy Hydrographic Dept Taunton UK DETAILED SURVEYS COMPILATIONS INCLUDED WITH LITTLE OR NO MODIFICATION 1 Aumento F Loncarevic B D and Ross D I 1971 Phil Trans Roy Soc London A 268 623 650 2 R R S Discovery II 1960 Unpublished survey Institute of Oceanographic Sciences Wormley U K 3 Kidd R B Searle R C Ramsay A T S Prichard H and Mitchell J 1981 Oceanologica Acta 4 Vogt P R and Ostenso N A 1966 J Geophys Res 71 4389 4411 5 Searle R C and Laughton A S 1977 J Geophys Res 82 5313 5328 6 Searle R C 1980 Earth Planet Sci Lett 51 415 434 7 Searle R C 1980 Unpublished chart Institute of Oceanographic Sciences Wormley U K 8 Laughton A S Roberts D G and Graves R 1975 Deep Sea Res 22 791 810 9 R R S Discovery II 1971 Unpublished survey Institute of Oceanographic Sciences Wormley U K 10 H M S Dalrymple 1955 and H M S Owen 1957 Unpublished surveys Hydrographic Department Taunton U K 11 H M S Ormonde 1933 Unpublished survey Hydrographic Department Taunton U K Page 119 of 141 12 Hydrographer of the Navy U K 1969 Chart C 6101 Hydrographic Department Taunton U K 13 Black M Hill M N Laughton A S and Matthews D H 1964 Q J Geol Soc Lond 120 477 517 14 R R S Discovery II 1958 Unpublished survey Institute of Oceanographi
204. s inhomogeneous and often very sparse and the data emanate from a wide diversity of sources with highly variable accuracy These problems are of course well familiar to the traditional bathymetrist forced to apply his her own interpretive skills in order to generate a coherent set of contours For these reasons the GEBCO gridding effort has concentrated primarily on making use of the GDA contours for generating a grid Since the GDA was first published in 1994 a small Working Group has operated within GEBCO researching the problems of generating a GEBCO grid and organising the creation of the grid The Working Group was led initially by Walter Smith of the US National Ocean Survey now at the NOAA Laboratory for Satellite Altimetry and latterly by Michael Carron and Bill Rankin of the US Naval Oceanographic Office In 1997 the Working Group Page 14 of 141 produced a draft paper On the preparation of a gridded data set from the GEBCO Digital Atlas contours It provided a comprehensive review of the problem including the needs of potential users mathematical considerations and the strengths and weaknesses of the various methods available to compile the grid It was decided that the GEBCO grid should be based on the most up to date version of the GDA contours and that computation of the grid should be carried out by a network of volunteering centres using common algorithms based on rubber sheeting techniques Members of the network we
205. s of United Nations Conferences on Geographical Names The resulting document entitled Standardization of Undersea Feature Names was published by the IHB as IHO IOC Publication BP 0006 now B 6 and may be found on the GEBCO website The Sub Committee played a key role in ensuring the standardization of the geographical names and nomenclature used for ocean bottom features on the sheets of the GEBCO Fifth Edition During the Ninth Session of the GEBCO Guiding Committee in 1983 the IHB was requested to prepare a Gazetteer of the geographical names of undersea features shown on the GEBCO Fifth Edition and on the IHO Small Scale INTernational Chart Series 1 2 25 million and smaller so that they could be used on other chart series and assist in the standardization of feature names The IHB accepted the task particularly since the small scale INT charts produced by IHO Member States were increasingly showing more detailed ocean morphology with more geographical names The first edition of the Gazetteer was published by the IHB in November 1988 as IHO IOC Publication BP 0008 now B 8 It included the geographical names shown on the GEBCO Fifth Edition and on the small scale INT charts published up to February 1988 as well as the new geographical names approved by the GEBCO Sub Committee on Geographical Names and Nomenclature of Ocean Bottom Features at its meeting in April 1987 The Gazetteer is kept updated by the IHB using a computer based system
206. shelf islands in the Arctic Circle An initial list of islands was prepared using the names printed on the sheets of the GEBCO Fifth Edition but this was then extended by reference to the Times Atlas of the World Comprehensive Edition particularly in the areas of Micronesia Melanesia and Polynesia in the Pacific Ocean In general an attempt was made to identify all isolated islands but in island groups only a few key islands were identified The name of the island group is included in parenthesis after the island name where appropriate Island names were taken either from the GEBCO Fifth Edition sheets or from the Times Atlas of the World and follow the naming and language conventions adopted by these two sources Inevitably the list contains a mixture of anglicised and local language names The geographic coordinates of each island were determined by reference to the World Vector Shoreline Using the GDA Software Interface each island was zoomed into in turn on a PC screen and the screen cursor was set within its confines the geographic coordinates of the cursor were then read off the automatic cursor coordinates display The GDA also includes a geographically referenced list of the Antarctic islands named on the GEBCO Fifth Edition sheets The island names were taken directly from these sheets and the geographic coordinates of islands close to the ice shelf were determined by reference to the digitised coastline of the GEBCO Fifth Edition
207. so called on Member States to invite publishers of ocean maps and editors of scientific journals in their country to require compilers and authors to provide written evidence of such clearance before accepting for publication any maps or scientific articles containing new names for undersea features GEOGRAPHIC NAMES IN THE GEBCO DIGITAL ATLAS The GEBCO Digital Atlas includes geographically referenced lists of the names of undersea features oceanic islands Antarctic islands Antarctic stations ports and cities This information is available to the user via queryable feature symbols that can be overlain on the map area of charts displayed on the user s screen through the GDA Software Interface In the case of undersea features extended information is displayed covering relevant details on the naming of the feature as stored in the IHO IOC Gazetteer Separate symbols are used for undersea features islands and place names on land It should be stressed that the use of geographic names in the GDA must not be construed as having any legal or political connotation whatsoever They are intended purely for geographic convenience and in the case of undersea features for encouraging the standardisation of names on nautical and bathymetric charts Undersea Features The IHO IOC Gazetteer of Geographical Names of Undersea Features is maintained at the IHB in Monaco on a computerised database system It is kept regularly updated with new geographica
208. t Petersburg Russia 3 sheets Alfred Wegener Institut Bremerhaven Germany 2 sheets Page 34 of 141 Quality control final editing and reformatting of these data into a uniform data set was again performed at BODC with the work being carried out over a 3 year period between 1990 and 1993 The Canadian Hydrographic Service kindly collaborated again by providing stable base transparencies of the master trackline control plates of the published Fifth Edition sheets for use in digitizing As before raster scanning techniques using laser scanning equipment provided the basis for the digitization with the final output being in the form of trackline vectors The outlines of survey boxes together with their supporting text were digitized as well as the individual ship tracklines In areas where sheets overlapped the tracklines were only digitized on the sheet from which the bathymetric contours had been digitized For the area of sheet 5 06 between 100 E and 180 E the tracklines were digitized from transparencies taken from the trackline plates used to produce the 1 1 million scale atlas published by the Japan Oceanographic Data Center which complemented the digital data set of bathymetric contours and coastlines already supplied to BODC for that area Likewise for the area of sheet 5 12 the tracklines were digitized from source material provided by the compilers of the revised bathymetry for the new version of the sheet The com
209. t in the coastline when plotted out at high scale For areas of the world not covered by the DLMB database the shoreline was taken from the best available hard copy sources at a preferred scale of 1 250 000 or up to 1 125 000 where the source data allowed The WVS is a truly impressive product but some uncertainty remains in that the accuracy specification 500m see above for 90 of WVS gives no indication of the accuracy for the remaining 10 of the world or where the areas of lesser accuracy occur It was anticipated that the main area of reduced accuracy occurred around Antarctica and with the publication of a high quality 1 1 million scale coastline of Antarctica by SCAR in 1993 it was decided to remove the WVS coastline south of 60 S and to replace it with the SCAR coastline Page 36 of 141 As yet the WVS has not been matched to the digitized bathymetric contours of the GEBCO Fifth Edition and isolated occurrences may arise where WVS appears in conflict with the bathymetry e g around oceanic islands and where the shoreline abuts a submarine scarp Such mismatch is mainly a consequence of the different scale and resolution of the two data sets The WVS is being phased in with the GEBCO bathymetry as and when the bathymetry is updated with new data This has already occurred for the revised bathymetry of GEBCO sheet 5 12 and the update sheets G 01 to G 09 where WVS was used as the source of the coastline north of 60 S In addition
210. t of the GEBCO Digital Atlas The legal copyright of the main components of the GEBCO Digital Atlas is held by the UK Natural Environment Research Council NERC on behalf of the Intergovernmental Oceanographic Commission of UNESCO and the International Hydrographic Organization through the Joint IOC IHO Guiding Committee for GEBCO The legal copyright of certain components is held separately ICSU Scientific Committee on Antarctic Research for the Coastline of Antarctica Head Department of Navigation and Oceanography St Petersburg for the First Edition of the International Bathymetric Chart of the Mediterranean International Hydrographic Bureau Monaco for the IHO IOC Gazetteer of Geographic Names of Undersea Features UK Hydrographic Office Taunton for the Third Edition Echo Sounding Correction Tables New Zealand National Institute of Water and Atmospheric Research for the Bathymetric Chart of the New Zealand Region Alfred Wegener Institute for Polar and Marine Research Bremerhaven for the Bathymetric Chart of the Weddell Sea Service Hydrographique et Oceanographique de la Marine Paris for IBCEA Sheets 1 06 1 08 1 09 1 10 1 11 and 1 12 Instituto Hidrografico Lisbon for IBCEA Sheet 1 01 Instituto Nacional de Estadistica Geografia e Informatica Mexico for IBCCA published sheets Page 4 of 141 NERC does not hold the copyright of the World Vector Shoreline of the IBCAO bathymetry of the GLOBE land elevatio
211. terranean CIM and was coordinated by the lOC ICSEM FAO Operational Unit for CIM in Monaco The work was progressed from 1974 to 1978 under the guidance of an Ad hoc Group of Experts on Bathymetric Charts of the Mediterranean This group was subsequently reshaped into the IOC Editorial Board for the IBCM One of the principles adopted in the preparation of IBCM was to accept only precision soundings with accurate navigation by satellite or comparable techniques read from echo sounder records corrected for the speed of sound Most of the data selected were navigated using Loran C with the positional accuracy varying from 100m in central areas e g the Tyrrhenian Sea to 600m in peripheral areas The soundings were compiled on 1 250 000 British Admiralty plotting sheets for oceanic soundings and the contours were drawn directly on these sheets before being reduced to 1 1 million The contours were drawn by scientists specialised in morphology and charting of the sea floor The bulk of the data available for the IBCM First Edition was collected on marine geophysical surveys undertaken by three institutions Between 1961 and 1965 112 000 km of track were surveyed by the Osservatorio Geofisico Sperimentale OGS of Trieste in cooperation with the Saclant ASW Research Centre in La Spezia Then between 1965 and 1972 the OGS acquired another 217 500 km of track primarily in the western and central Mediterranean but also including a reconna
212. th in corrected metres Contours present Bay of Biscay and IBCEA Sheet 1 01 contain contours at 200m intervals also included in the digital data but not on the published charts are contours at 500m and at 1000m intervals thereafter IBCEA Sheet 1 01 also includes contours at 50m 100m and 150m Madeira Strait of Gibraltar contains contours at 20m 50m 100m and at 100m intervals thereafter Additional intermediate contours may be found in abyssal areas Coastline Source NIMA World Vector Shoreline at a scale of 1 250 000 Geographic Coverage 32 10 N 42 N 15 20 W 5 15 W 42N 47 N 16W O W 47 N 48 N 13 W 11 30 W and 7 30 W 1 W plus an irregular area within 31 N 32 40 N 18 W 14 W Within the above area IBCEA Sheet 1 01 was used in the area north of 36 N between 15 20 W and 7 20 W and south of 44 N between 12 W and 7 20 W but south of 43 N between 15 20 W and 12 W Digitization Contours and tracklines for Areas A and C were digitized by BODC while contours for Area B were digitized by Instituto Hidrografico Lisbon Page 74 of 141 Published Charts Sibuet J C Monti S and Pautot G 1994 New bathymetric map of the Bay of Biscay C R Acad Sci Paris t 318 s rie Il p 615 625 including map published at a scale of 1 2 4 million Chart Limits 43 N 49 N 18 W 1 W Instituto Hidrografico 2002 Sheet 1 01 of the International Bathym
213. the bathymetry was updated as and when appropriate As a result of this over 600 sections of update charts were delivered to BODC for digitising during the project in addition to the 250 first version sheets The work was completed in September 2002 DATA SOURCES USED FOR GEBCO SHEET G 08 During the compilation of data for GEBCO Sheet G 08 the oceanic scale 4 inches per degree longitude Mercator projection sounding compilation sheets maintained at SIO were augmented by shipboard data from the following sources individuals responsible for contributing the data are named in parenthesis 1 Principal sources collector sheets 1 1 GEBCO Collected Soundings Sheets 1 1 million scale Mercator maintained by Volunteering Hydrographic Offices with geographic responsibilities within the region a U K Hydrographic Department Taunton complete collection including Southern Ocean updated to 1988 1989 Nigel Gooding Brian Harper b South Africa Hydrographic Office Tokai Cape complete collection variously updated to 1981 1983 C G H Wagenfeld D B MacPherson c Hydrographic Office Royal Australian Navy Garden Island and Wollongong NSW 57 sheets variously updated to 1971 1989 Mark A Bolger 1 2 USNOO Bay St Louis Mississippi USNS Wilkes 1977 1979 1981 82 operations Francis Marchant Luther Little 2 Principal sources digital files 2 1 Government agencies a Australian Antarctic Division Kingston T
214. the western section and Kane in the eastern section of this area The spacing between sounding lines is 1 8km 4 Bathymetric contours taken from the map by Jacobs et al Jacobs C L Edgar N T Parson L M Dillon W P Scanlon K M and Holcombe T L 1989 A revised bathymetry of the Mid Cayman Rise and the Cayman trough using long range side scan sonar Institute of Oceanographic Sciences Deacon Laboratory report no 272 11p map The coastline is based on the US NIMA s World Vector Shoreline updated with data of the coastline generated from the cartographic series of Mexico topographic maps at a scale of 1 250 000 scale from the DGG of the INEGI IBCCA SHEETS 1 07 AND 1 08 Documentation not available at the time of going to press with the GEBCO Digital Atlas IBCCA SHEET 1 09 Scientific Coordinator Troy L Holcombe MGG NGDC Compilers Lisa A Taylor Jason Maddox Robert Mandzi Dan Metzger MGG NGDC Sources of detailed surveys and bathymetric contours Numbers correspond to numbered areas shown on the printed chart 1 U S Naval Oceanographic Office surveys trackline spacing generally 1 10 km Adapted from bathymetric contours by Joseph P Flanagan Joseph G Gilg Charles R Jones Francis L Marchant Robert R Murchison Jack H Rebman Lavern W Snodgrass Frederick H Sorenson and Joseph C Whitney compiled at Page 71 of 141 8a scale 1 1 000 000 and published by the National Oceanic and
215. tized the GEBCO Page 8 of 141 community has updated the bathymetry of about one third of the world s oceans Just as importantly the Centenary Edition also includes the first release of the GEBCO Bathymetric Grid providing bathymetric data on a one minute global grid This data set represents a major step forward for GEBCO and its creation owes much to the untiring efforts of a small group of volunteering experts Accompanying the Centenary Edition is a Microsoft Windows software interface which enables users to view the GEBCO bathymetry in a variety of forms and projections and to select and download contour vectors and gridded data for use in their own applications One important aspect of GEBCO which is continued in the Centenary Edition of the GDA is the inclusion of trackline information highlighting the coverage of data used in its compilation This is intended to act as a continual reminder to users that the world s oceans have not been systematically surveyed and that for virtually all areas of the oceans the mapping is based on the interpretation of random tracklines of data from a multitude of sources and with highly variable data quality and coverage Figure 1 Geographic coverage of sheet areas digitised from the GEBCO Fifth Edition to form the First Release of the GEBCO Digital Atlas issued in 1994 20E IFE 180 90 W o 205 20 E 110E 180 160 W TOW 20 E Page 9 of 141 2 0 CONTENTS OF THE CENTENARY EDITION
216. to its full resolution version simplified versions of WVS also exist at scales corresponding to 1 to 43 million 1 to 12 million 1 to 3 million 1 to 1 million and 1 to 250 000 The lower resolution data sets are simplified versions of the basic product obtained by filtering out points using the Douglas Peucker algorithm so as to produce a lower data volume In its original form the WVS was organized in one degree square units and shoreline continuity was ensured by including the coordinates of all shoreline crossovers with whole degree latitude and longitude lines These points appear to have been retained at each step during the simplification process with the result that for the 1 43 million scale shoreline they appear to have a disproportionate influence on the simplified shoreline However this effect is only noticeable if the shoreline is viewed at scales greater than 1 43 million and serves to illustrate that the simplified shorelines should only be used at scales less than or equal to their nominal scales South of 60 S the SCAR coastline is also available at a range of scales and these have been matched to WVS as follows WVS 1 43 million with SCAR 1 10 million WVS 1 12 million with SCAR 1 10 million WVS 1 3 million with SCAR 1 5 million WVS 1 1 million with SCAR 1 1 million WVS 1 250 000 with SCAR full resolution Page 37 of 141 ANNEX E SCAR Coastline of Antarctica Note The SCAR coastline has been a
217. ts displayed on the user s screen through the GDA Software Interface Separate symbols are used for undersea features islands and place names on land The IHO IOC Gazetteer of Geographical Names of Undersea Features which is maintained at the International Hydrographic Bureau IHB in Monaco on a computerised database system forms the authoritative source of undersea feature names It is kept regularly updated with new geographical names as and when they are approved by the GEBCO Sub Committee on Undersea Feature Names SCUFN A copy of the IHB database was used as the source material for the undersea feature names in the GDA and it includes all names approved by SCUFN up to September 2002 Information extracted from the Gazetteer for each undersea feature and which may be viewed on the user s screen when the feature is queried through the GDA Software Interface includes a the geographical name of the feature and the generic term used to define the nature of the feature b the geographical position of the feature this is only an approximate position and is used solely to identify the feature rather than to define its precise location Where the feature is extensive a second position may also be given to indicate its extent For linear features such as ridges and fracture zones further positions may have been added by BODC to delineate the feature c areference to the GEBCO sheets IHO Small Scale International Charts using the pre
218. tting sheets on Mercator projection at a scale of 1 1 million projection From these plotting sheets the contour lines were compiled and soundings for inclusion on the GEBCO 1 10 million series were selected Publication began in 1932 but work on the Third Edition progressed slowly and was never completed the effect of World War II and the rising flood of new data were contributing factors but the main reason was the lack of financial support which restricted deployment of resources to a single draughtsman Fourth Edition The Vith International Hydrographic Conference 1952 saw the need for a Fourth Edition of GEBCO and with the amount of bathymetric data continuing to increase rapidly decided that the sheets should be updated on a 5 year cycle Consequently the Fourth Edition was started in 1958 before the Third Edition had been completed The 2 sheets published in 1958 and 1961 were the last to be based on compilations prepared by the IHB To produce further sheets from the great wealth of new data becoming available was clearly beyond the resources of the Bureau alone and accordingly a new organisational structure was evolved The responsibility for maintaining the 1 1 million plotting sheets was taken over by 18 volunteering Hydrographic Offices of IHO Member States each responsible for a specific area of the world s oceans The IHB co ordinated the scheme ensuring the flow of bathymetric soundings to the appropriate Hydrographic Office
219. tute of Water and Atmospheric Research NIWA Wellington New Zealand Digitised by Nichola Litchfield contours and Dave Cook tracklines CANZ Group NIWA Sheet Limits 24 S to 57 30 S 157 E to 167 W Scale eee compiled and digitized on Mercator sheets at a scale of 1 1 million Horizontal Datum WGS 84 Contour Units bathymetric depth in corrected metres Contours present Om 50m 100m 150m 200m 250m and at 250m intervals thereafter down to 10 000m Coastline Source NIMA World Vector Shoreline 1 250 000 scale Published Chart CANZ Group 1997 New Zealand Region Bathymetry 1 4 000 000 scale at 46 S on Mercator projection NIWA Chart Miscellaneous Series No 73 National Institute of Water and Atmospheric Research Wellington New Zealand Geographic Coverage In the edgematching of this sheet with GEBCO sheet G 08 the bathymetry was taken from sheet G 08 for the following areas 24 31 S 157 158 5 E 47 54 S 157 165 E 54 57 5 S 157 163 5 E PREPARATION OF GEBCO SHEET G 09 The bathymetry was compiled by NIWA at a scale of 1 1 million using a series of 18 separate Ocean Plotting Sheets on which the soundings were plotted Each author as listed above worked on the interpretation and contouring of 3 4 sheets each and gravity data were used to assist in the interpretation The resulting contours at intervals of 250m were then digitized and used in the production of the 1 4 million scal
220. two codes are only present in files exported through the GDA Software Interface when the user has requested that feature codes 22010 to 22023 and 22090 and 22100 should be combined into feature code 1 and feature codes 22030 to 22050 into feature code 2 Page 24 of 141 TABLE 4 Proprietary Output Formats for GDA Vector Data In addition to simple flat ASCII format the user may also export vector data through the GDA Software Interface in the two commonly used GIS formats DXF and ESRI Shapefile DXF Format DXF originated as a proprietary format in the commercially available AUTOCAD package but is now a standard input format for many other commercially available software packages In DXF the vector streams are expressed as polylines in geographic co ordinates with each contour depth and coastline feature type assigned to a separate layer and a separate logical colour Likewise separate layers and logical colours are also assigned for tracklines survey boxes and sounding points The latter are expressed as type POINT rather than polylines Each of the layers is labelled using the feature code definitions listed in Table 3 ESRI Shapefile This format is used by ESRI products such as ARCINFO Further information about the Shapefile format may be found in http www esri com library whitepapers pdfs shapefile pdf Bathymetric contour coastline and trackline data are exported as li
221. ute of Oceanographic Sciences Wormley U K 36 Belderson R H and Laughton A S 1966 Sedimentology 7 103 116 37 Ulrich J 1969 In Closs H Dietrich G et al Reisebericht Meteor Forschungsergebnisse Reihe A no 5 21 23 38 Defant A 1939 In Defant A and Helland Hansen Bj Abhandlungen der Preussischen Akademie der Wissenschaften Physikalisch mathematische Klasse Nr 5 40 45 39 Searle R 1977 Mar Geol 25 299 320 40 Heezen B C and Johnson G L 1963 Deutsche Hydrographische Zeitschrift 16 269 272 41 Weiland D 1976 Erarbeitung und Diskussion einer topographische morphologischen Meeresbodenkarte im Seegebiet nordlich Dakar Senegal Geogr Inst Univ Kiel 42 Twight W Slootweg A P and Collette B J 1979 Mar Geophys Res 4 91 104 43 Asquith S M 1979 Mar Geol 32 165 190 44 Bush P A 1976 Deep Sea Res 23 1105 1113 Also Embley R W and Jacobi R D 1977 Mar Geotechnology 2 Marine Slope Stability Crane Russak and Co Inc 205 227 45 Flood R D 1978 Ph D Thesis Wood s Hole Oceanographic Institute 394 pp 46 Johnson G L and Vogt P R 1971 Deep Sea Res 18 605 617 Also Kumar N and Embley R 1977 Geol Soc of Amer Bull 88 683 694 47 Moody R Hayes D E and Connary S 1979 Bathymetry of the Continental Margin of Brazil Amer Assoc of Petrol Geol Tulsa Oklahoma U S A Also Rabinowitz P D and Ludwig W J
222. w continued with the release of the Centenary Edition of the GDA In addition to the bathymetry of the GEBCO Fifth Edition the First Release of the GDA also included the digitized contours and coastline of the 1 1 million scale First Edition of the International Bathymetric Chart of the Mediterranean IBCM see Annex J Unfortunately the trackline control information from the IBCM was not digitized Furthermore as the Mediterranean is essentially a closed sea in the cartographic sense the IBCM data set was not merged with the GEBCO contours but rather left as a stand alone data set This separation continues in the Centenary Edition In recent years GEBCO has been able to benefit from outputs provided by a number of IOC Regional Ocean Mapping Projects in addition to the IBCM including the International Bathymetric Chart of the Caribbean Sea and Gulf of Mexico IBCCA the International Bathymetric Chart of the Central Eastern Atlantic IBCEA and the International Bathymetric Chart of the Arctic Ocean IBCAO Unlike the IBCM the 1 1 million scale outputs made available from these projects have been stitched into the GEBCO bathymetry Since 1994 the bathymetry of about one third of the world s oceans has been revised and submitted to BODC for updating the GEBCO Digital Atlas The geographic coverage of the revised material is shown in fig 2 where the updated areas are numbered in the sequence G 01 to G 09 These comprise the following c
223. was published standard correction tables have been used to correct for the true speed of sound in seawater for this purpose the world s oceans are divided into discrete areas linking regions with common sound velocity profiles and a table is constructed for each area with the depth correction to be applied at various depths down the water column In 1939 a Second Edition of Matthews Tables was published and these tables remained in common use until the early 1980s Matthews D J 1939 Tables of the velocity of sound in pure water and sea water for use in echo sounding and sound ranging Second edition British Admiralty Hydrographic Department Publication H D 282 London 52p In 1980 a Third Edition of the Echo Sounding Correction Tables was published by the U K Hydrographic Department to replace Matthews Tables The tables were extensively revised to incorporate the large number of temperature and salinity measurements obtained since 1939 and used an improved formula for the dependence of sound velocity on temperature and salinity Computations for the revised tables were carried out by D J T Carter of the Institute of Oceanographic Sciences Wormley England using oceanographic station data provided by the U S National Oceanographic Data Center Washington The revised tables together with a detailed description of their preparation may be found in Echo Sounding Correction Tables Third Edition in Publication N P 139 of the U K Hydr
224. y Ocean Area N A 9 1 Geophysical Maps of the Eastern Caribbean U S Naval Oceanographic Office Reference Publication RP 3 Page 72 of 141 8b Multibeam surveys from the ARCANTE 2 THERMOSITE expedition published in Bouysse P Robert S Guennoc P and Monti S 1963 Bathymetrie detaillee seabeam et anomalies magnetiques dans les Antilles Francaises Documents du B R G M no 63 78 p 8c Multibeam survey from the SEACARIB 1 expedition R V Conrad 1985 9 Bathymetric contours from Troy L Holcombe Cynthia G Fisher and Frederick A Bowles 1989 Gravity Flow Deposits from the St Croix Ridge Depositional History Geomarine Letters v 9 p 11 18 Trackline spacing ranges from 0 2km to 2 km Tracklines shown for the remaining area are from the digital data files of the U S National Geophysical Data Center Trackline control from Matthews J E and Holcombe T L 1976 Regional Geological Geophysical Study of the Caribbean Sea Navy Ocean Area NA 9 1 Geophysical Maps of the Eastern Caribbean Naval Oceanographic Office Reference Publication RP 3 was also incorporated in the Venezuelan Basin area Imagery from the side scanning sonar system GLORIA II obtained by the U S Geological Survey for the areas shown in the inset map was employed in interpretation of bathymetric contours Published GLORIA II images appear in EEZ SCAN 85 Scientific Staff 1987 Atlas of the U S Exclusive Economic Zone Gulf of Mexico and Easter
225. y and often concentrated on isolated tracklines with large gaps in between When the earlier editions of GEBCO were produced there was no adequate understanding of the nature and scale of processes which first create and then modify the variety of morphological features of the ocean floor Only when the theory of Plate Tectonics was developed in the late 1960s did it become possible to understand the processes involved in shaping the ocean floor The knowledge base developed from the geological and geophysical research of the period enabled scientists cautiously but with increasing confidence to infer major linear trends and thus to interpolate between sounding lines in order to produce more meaningful bathymetric charts This scientific approach to bathymetric mapping was to become one of the key features of the preparation of the Fifth Edition of GEBCO Page 28 of 141 ANNEX B Production of the GEBCO Fifth Edition In 1972 realising the need for a modernised GEBCO series the IHO and the IOC decided to co sponsor an entirely new edition of the GEBCO to be compiled by marine scientists employing the best available geological and geophysical knowledge of the sea floor Production of the series was supervised by a Joint IOC IHO Guiding Committee for the GEBCO composed of ten members five nominated by the IHO and five by the IOC The IHO experts were selected from volunteering Hydrographic Offices in their Member States whereas the IOC experts w
226. y and is presented on disc 2 in Directory GRIDFIVE as a standalone file directly accessible to the user This version of the grid is not accessible through the GDA Software Interface and is aimed primarily at existing users of the ETOPO5 database Page I5 of 141 3 3 Coastlines Once the GEBCO Digital Atlas had been initialized by digitizing the published sheets of the GEBCO Fifth Edition the updating of GEBCO bathymetry was no longer constrained by scale However by its very nature the GEBCO Fifth Edition coastline based primarily on the Carte G n rale du Monde of the Institut Geographique National Paris was suited only for use at scales of the order of 1 10 million In 1989 a search was instigated for an alternative coastline satisfying the criteria that it should be a digital b suitable for use at scales up to 1 250 000 c global in coverage and d of consistent accuracy across the globe It was fortunate that just at that time the US Defense Mapping Agency DMA released its World Vector Shoreline WVS see Annex D the only coastline able to satisfy the GEBCO criteria Following a review of the WVS the GEBCO Guiding Committee agreed that it should be adopted as the standard coastline for future use in GEBCO and the DMA generously gave GEBCO permission to use WVS in the GEBCO Digital Atlas The WVS has also been adopted as the standard coastline for use in IOC s Regional Ocean Mapping Projects In non polar regions of the w
227. y celebrations in April 2003 It is a great personal pleasure to see the publication of the Centenary GDA in the year that retire from GEBCO having been a member of the GEBCO Committee since 1966 and Chairman of the Guiding Committee since 1986 commend the Centenary GEBCO Digital Atlas to all Sir Anthony Laughton Chairman of the Joint IOC IHO Guiding Committee for GEBCO Page 2 of 141 Acknowledgements The GEBCO Digital Atlas project is carried out under the auspices of the Intergovernmental Oceanographic Commission IOC and the International Hydrographic Organization IHO It is overseen by the Joint IOC IHO Guiding Committee for GEBCO and technical guidance is provided by the GEBCO Sub Committee on Digital Bathymetry The British Oceanographic Data Centre is responsible for updating maintaining quality controlling and publishing the GEBCO Digital Atlas This work is funded by the UK Natural Environment Research Council The continued development of the GEBCO Digital Atlas would not be possible without the untiring efforts of the countless marine scientists and hydrographers who continue to collect echo sounding measurements across the world s oceans Likewise it also depends on the efforts of the many hydrographic offices marine laboratories government agencies and university departments who assemble maintain and make these data available for use by GEBCO But most of all it depends on those individuals responsible for com
228. y version is stored on disc 1 for user selected display export via the GDA Software Interface while an ASCII version is stored on disc 2 for users requiring direct access h a digital set of geographically referenced feature names including the IHO IOC Gazetteer of Geographical Names of Undersea Features a list of the ports cities and Antarctic islands portrayed on the printed sheets of the GEBCO Fifth Edition a list of Antarctic stations and a specially prepared list of oceanic islands An internal version is stored on disc 1 for interactive display and querying via the GDA Software Interface This information is not directly accessible to the end user i a digital version of the Third Edition of the IHO Echo Sounding Correction Tables stored on disc 1 both for direct access by the end user and for use within the GDA Software Interface Comprehensive documentation on the above data sets is contained in the Annexes of this User Guide In particular detailed information is provided on each of the charts used in the compilation of the GEBCO contours Annexes K and L This information includes the authorship and specification of each chart and information on the methods by which each chart was compiled including the data sources used Detailed documentation on the generation of the GEBCO One Minute Grid may be found in the User Guide to the GEBCO One Minute Grid Figure 2 Geographic coverage of sheet areas digitised to form the Cente
229. ymetry Intermediate contours were only edgematched if present on both sides of the boundary Incorporating the new sheets into the GDA involved the assimilation not only of the contours and associated coastlines but also of the trackline control information identifying the echo sounding data available for compiling the contours Trackline control information is stored in one of three forms each identified in the data with a different feature code as trackline vectors as locations of individual soundings or as documented survey boxes In the latter case the outlines of the survey boxes are digitised and linked with an explanatory note which is available to the user through the GDA Software Interface by setting the cursor in query mode within the area of the survey box Survey boxes often indicate areas of high quality surveys or saturated sounding coverage but they may also represent areas where pre compiled bathymetric contours were taken from other sources It will be noted that much of the new material was compiled at scales of the order of 1 1 million i e at a considerably enhanced scale compared with the 1 10 million scale of the GEBCO Fifth Edition This reflects the move of GEBCO away from the fixed scale paper chart and the ultimate goal of enhancing GEBCO with the best available bathymetry It should be stressed that the assignment of a scale to a bathymetric sheet simply reflects the scale of the compilation sheet used in its preparati

User Guide to the Centenary Edition of the GEBCO Digital Atlas

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