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Meridian™ user guide

1. Ordnance Survey Meridian user guide chapter 6 v3 0 12 2000 Crown copyright Page 6 3 Ordnance Survey Meridian user guide chapter 6 v3 0 12 2000 Crown copyright Page 6 4 POINTREC 45 LINEREC og GEOMETRY1 24 POINT FEATURE GEOMETRY1 21 LINE FEATURE LINE GEOMETRY GEOMETRY BODY GEOMETRY CONTINUATION RECORDS 00 ATTREC 14 ATTREC 14 NODE RECORD NODEREC 416 NODE CONTINUATION RECORDS 00 TEXTREC 43 44 TEXTPOS GEOMETRY1 24 NODE FEATURE TEXTREP 45 POINTREC jg ATTREC jg GEOMETRY1 ATTREC 21 4 The governing body for the industry standard NTF is the British Standards Institution BSI Their address is British Standards Institiution 389 Chiswick High Road LONDON W4 4AL Phone 44 0 20 8996 9000 Fax 44 0 20 8996 7400 Email info bsi global com Any queries relating to the Meridian 2 product should be referred to the Sales Information Helpdesk at the address given in Contact details at the beginning of this user guide Ol Ordnance Meridian user guide chapter 6 v3 0 12 2000 Crown copyright 1 Survey Page 6 5 Meridian user guide chapter 6 Oo Ordnance v3 0 12 2000 Crown copyright Survey Page 6 6 Transfer set structure Record size NTF data is written to the output
2. Survey Meridian user guide chapter 4 v3 0 12 2000 Crown copyright Page 4 3 Meridian user guide chapter 4 Oo Ordnance v3 0 12 2000 Crown copyright m Survey Page 4 4 Each Meridian 2 10 km by 10 km tile is described by adding a two digit reference to the 100 km by 100 km square reference with the easting first followed by the northing for example TG23 HT For additional information on how to use the HW HX HY National Grid visit Ordnance Survey s web site at www ordnancesurvey co uk To NA NB NC ND 5 navigate to the National Grid site click on the Education icon in the menu and then on NG NH NL NVMZNN 7 i KR SZ NA NS NT NW NX NY Mac SD mae SJ Zn SM SN ve SO Chapter 5 The National Grid Meridian 2 tiles are identified by quoting the National Grid reference of the south west corner of the area they cover The Ordnance Survey National Grid divides Great Britain into squares 100 km by 100 km Each of these squares has a unique two letter reference for example TG in the diagram below 100 km by 100 km square TG SV SR SS LE SW SX TV ST Crown copyrigh rZ SY 2 10 km by 10 km square TG 23 Meridian user guide chapter 5 v3 0 12 2000 Crown copyright Page 5
3. Ordnance Survey Meridian user guide chapter 6 v3 0 12 2000 Crown copyright Page 6 21 Meridian user guide chapter 6 Oo Ordnance v3 0 12 2000 Crown copyright Record structures for the transfer of Meridian 2 in NTF Chapter 7 NTF Record List This list comprises the valid record types used in the Meridian 2 NTF transfer Set Descriptor 01 02 05 07 14 15 16 21 23 40 43 44 45 90 99 Description Volume Header Record defines the donor and data type Database Header Record transfers data about the database Feature Classification Record defines data classifications Section Header Record defines coordinate and structure types unit scale factors and so on Attribute Record defines the attributes for line and point records Point Record identifies the definition of node points Node Record defines the topological relationship between links and nodes Two dimensional Geometry Record defines the two dimensional geometry for a link or node Line Record identifies the definition of a link Attribute Description Record defines attribute descriptions and their fields Text Record identifies the Text Position Record and Attribute Record Text Position Record identifies the Text Representation Record and Geometry Record Text Representation Record defines the font text height and digitised position Comment Record transfers change information or
4. i Ordnance ou GO Rae v3 0 rown copyright Survey Page 9 23 Meridian user guide chapter 9 oO Ordnance v3 0 12 2000 Crown copyright Figure 9 15 Level 3 0 Key POLYLINE one or more ENTITY o optional VERTICES FOLLOW FLAG GROUP POLYLINE GROUP 0 0 Y Z GROUP GROUP 0 0 POLYLINE g DEFAULT DEFAULT SEQ END FLAG GROUP STARTING ENDING VERTICES GROUP WIDTH GROUP WIDTH GROUP Figure 9 16 Figure 9 16 Vertex entity level 4 Key one or more o optional VERTICES VERTEX GROUP X GROUP o STARTING ENDING GROUP WIDTH End of File Group This group will end with DXF EOF End Of File group Ol Ordnance Figure 9 15 Y GROUP VERTEX FLAGS Z GROUP o CURVE FIT TANGENT DIRECTION survey Meridian user guide chapter 9 v3 0 12 2000 Crown copyright Page 9 25 Meridian user guide chapter 9 Oo Ordnance v3 0 12 2000 Crown copyright Appendix A Glossary accuracy The closeness of the results of observations computations or estimates to the true values or the values accepted as being true Accuracy relates to the exactness of the result and is the exactness of the operation by which the result is obtained administrative area A blanket term used by Ordnance Survey to refer to all public administrative areas specifically local government management and electoral areas American Standard Code for Informa
5. this uniquely identifies the hydrology inland water seed Woodland identifier this uniquely identifies the woodland seed The unique identifiers are unique references and are maintained except where there has been significant change to a feature The unique identifier may refer to several links representing a linear object across tiles for example a road ora railway which may be chained together across tile edges Thus on adjoining tiles there may be two or more links with the same unique identifier see figures 6 1 and 6 2 Record IDs The identifying fields for each NTF record for example NODE_ID for NODEREC LINE_ID for LINEREC and so on are unique within each individual section tile supplied They are not maintained between supplies Ordnance survey Meridian user guide chapter 6 v3 0 12 2000 Crown copyright Page 6 17 Meridian user guide chapter 6 oO Ordnance v3 0 12 2000 Crown copyright Survey Page 6 18 Figure 6 1 Example of a unique identifier OSODR Figure 6 2 Example of unique identifier a railway and railway station Tile id ST68 Tile id ST88 LINE_ID 41 LINE_ID 71 LINE_ID 62 LINE_ID 130 LINE_ID 22 OSODR ODJ945LPCABAX Tile id ST86 Tile id NT68 Tile id NT88 NODE_ID 23 LINE_ID 41 LINE_ID 153 Railway identifier 38231 10682322 Railway station identifier 332110684101 LIN
6. Administrative areas and roads data have a 20 m lateral filter applied to the boundary and centre lines The 20 m filter does not affect the positional accuracy of node points Features derived from the small scale databases have been subjected to generalisation information is cartographically represented in areas where accurate positional representation would cause confusing clutter on the viewed image To maintain positional relationships such data has been further adjusted to fit the hierarchy where necessary Completeness During production many checks are undertaken to ensure that data supplied to customers are both accurate and complete During digital manipulation in creating the upgraded data all sources of that data are checked against specification documentation to ensure that no features have been omitted or misaligned These quality control checks take the form of visual checks by operators independent quality assurance checks and computer validation with the specification Meridian general specifications The following gives details of the product specification identity and their relationship to Ordnance Survey data capture specifications Version details of these specifications are also stated Product Product specification Meridian 2 Meridian_02 00 Transfer format specifications Name NTF BS 7567 Level 3 Version 2 Issue Date 15 May 1992 DXF Release 12 1 1 January 1997 LO Ordnance
7. feature classification record A specific named NTF record which lists the feature codes in use in the current database feature code FC An alphanumeric attribute code used in digital map data to describe each feature in terms of the object surveyed its representation on the map or both feature serial number FSN A number used as a feature identifier usually allocated on a sequential basis For example the order in which features are digitised field A specific part of a record containing a unit of data such as the date of digitising The unit of data may be a data element or a data item In NTF a field is a subdivision of a physical record Every field has a name and a pre defined interpretation file An organised collection of related records The records on a file may be related by a specific purpose format or data source the records may or may not be arranged in sequence A file may consist of records fields words bytes characters or bits font The style of text character used by a printer or plotter format The specified arrangement of data For example the layout of a printed document the arrangement of the parts of a computer instruction the arrangement of data in a record geographical information system GIS A system for capturing storing checking integrating analysing and displaying data that is spatially referenced to the Earth This is normally considered to involve a spatially referenced comput
8. l Tile n data l 9 VOLUME TERMINATION RECORD j 99End Of Transfer Set 0 Ol Ordnance Meridian user guide chapter 6 ai v3 0 12 2000 Crown copyright d Survey sig oO Ordnance Meridian user guide chapter 6 a v3 0 12 2000 Crown copyright Survey Page 6 8 Formatted media transfer set greater than media capacity VOLUME HEADER RECORD DATABASE HEADER RECORD ATTRIBUTE DESCRIPTION RECORD FEATURE CLASSIFICATION RECORD SECTION HEADER RECORD VOLUME HEADER RECORD Remainder Tile 1 data VOLUME TERMINATION RECORD Part Tile 1 data VOLUME HEADER RECORD DATABASE HEADER RECORD ATTRIBUTE DESCRIPTION RECORD Me OE one i Pe S FEATURE CLASSIFICATION RECORD Continues On Volume 0213 SECTION HEADER RECORD VOLUME TERMINATION RECORD Kk Tile 2 data VOLUME TERMINATION RECORD i 99Knd Of Transfer Set 0 The beginning of each transfer set is structured with the following introductory or leading records Database Header Record DBHREC this gives details of A 2 3 4 The database name NTF release date Feature classification table name Release date that applies to the whole of the transfer set Attribute Description Record ATTDESC this lists and gives a description of the attributes that can be applied to features within the transfer set Feature Classification Record FEATCLASS this lists and gives descriptions of all possible feature codes for the transfer set
9. o Ordnance Survey www ordnancesurvey co uk Meridian 2 User guide v3 0 Contact details This user guide contains all the information you need to make effective use of Meridian 2 It is designed to help you understand the information contained in the data as well as providing detailed technical information and the data format specification This user guide has been checked and validated before issue and every endeavour made to ensure that the contents are accurate If you find an error or omission or otherwise wish to make a suggestion as to how this user guide can be improved please contact us at the address shown under Contact details The contents of this user guide will be updated by the release of replacement chapters Sales Information will be pleased to deal with your enquiries Sales Information Helpdesk Phone 08456 05 05 05 Fax 023 8079 22615 Email enquiries ordsvy gov uk or write to Sales Information Ordnance Survey Romsey Road SOUTHAMPTON United Kingdom S016 4GU Visit the Ordnance Survey web site at www ordnancesurvey co uk Oo Ordnance 1 Survey Meridian user guide v3 0 12 2000 Crown copyright OS granane Rs Sone 1 Survey Product performance If you have any problems with or identify any errors in the data or this user guide please complete the Product performance report form at appendix B and return it to us Liability A full descripti
10. or if variable See below Divider See below Divider No further records 6 7 8 12345678901234567890123456789012345678901234567890123456789012345678901234567890 Record example for a variable record 40JN A 1 2 Template JUNCTION_NAME Name Of Road Junction 0 3 4 6 7 8 12345678901234567890123456789012345678901234567890123456789012345678901234567890 Template Text Record TEXTREC 43 Field Position Format Value example Description REC_DESC 01 02 A2 43 TEXT_ID 03 08 16 Unique text record identifier NUM_SEL 09 10 12 01 SELECT 11 12 A2 00 TEXT_CODE 13 16 A4 0000 TEXP_ID 17 22 16 Pointer to TEXTPOS record NUM_ATT 23 24 12 01 ATT_ID 25 30 16 Pointer to ATTREC record CONT_ MARK 31 31 l1 0 No further records EOR 32 32 Al Record terminator Record example 4300000701000000000007010002670 1 2 3 4 5 6 7 8 12345678901234567890123456789012345678901234567890123456789012345678901234567890 Template i Ordnance Meridian user guide chapter 7 Survey v3 0 12 2000 Crown copyright Page 7 29 Oo Ordnance Survey Meridian user guide chapter 7 v3 0 12 2000 Crown copyright Page 7 30 Text Position Record TEXTPOS 44 Field Position Format REC_DESC 01 02 A2 TEXP_ID 03 08 16 NUM_TEXR 09 10 12 TEXR_ID 11 16 16 GEOM_ID 17 22 16 CONT_ MARK 23 23 11 EOR 24 24 Al Record example 44000007010000070002670 Va
11. There is no explicit information to identify which link forms the bounds of a particular area The whole developed land use area has been positioned to the road pattern by best fit practice Hierarchical position 4 i Ordnance Meridian user guide chapter 3 v3 0 12 2000 Crown copyright 1 Survey Page 3 17 Meridian user guide chapter 3 oO Ordnance v3 0 12 2000 Crown copyright 5 Cartographic names Place names from the small scales database and railway station attribute names are shown as independent text features and located near the feature that they describe Place names are collapsed from double banked treble banked or composite text to a single text feature with all the text as one string The text font STANDARD and text height in metres have been used for these cartographic names and are as layers separate from the feature with which they are associated These are the text font identifiers 0001 has been used for railway text Times Roman non italic 0002 has been used for settlement text Helvetica bold sans relief 0003 has been used for water text Times Roman italic sans these are transferred with the text feature 0004 has been used for town text Univers medium Roman condensed and text height in millimetres The Ordnance Survey convention for the digitising of names is as follows all names are digitised as point features given as X and Y National Grid coordinat
12. VAL_TYPE baal A2 JN VALUE A Junction name DIVIDER Al Divider VAL_TYPE Lu A2 SN VALUE AE A Settlement name DIVIDER TE A1 Divider VALUE TYPE ik A2 RT VALUE pea Al Roundabout CONT_MARK aca 11 0 No further records or 1 or continuation record follows EOR cg Al Record terminator Note variable integer Record example 140000230D03DF42CKOVTEGFC3500NP03P001J945LPCABATPOO14 2WFUP8 0AA0 POO1CV3 3LKPCBXE1 OOJNM27 J2 SNSOUTHAMPTON RTY0 12345678901234567890123456789012345678901234567890123456789012345678901234567890 Template Note PO records will be repeated NP number of times Continuation records will be used if necessary Oo Ordnance Meridian user guide chapter 7 v3 0 12 2000 Crown copyright 1 Survey Page 7 11 i Ordnance Survey Meridian user guide chapter 7 v3 0 12 2000 Crown copyright Page 7 12 Attribute Record ATTREC 14 for administrative area links county district coastline and neat line Field Position Format REC_DESC 01 02 A2 ATT_ID 03 08 16 VAL_TYPE 09 10 A2 VALUE 11 14 14 AL_TYPE 15 16 A2 VALUE 17 22 16 AL_TYPE 23 24 A2 VALUE 25 30 16 VAL_TYPE 31 32 A2 VALUE 33 38 16 AL_TYPE 39 40 A2 VALUE 41 46 16 CONT_ MARK 47 47 11 EOR 48 48 A1 Record example 14000014FC6405LC043050RC043084LD069234RD0697200 3 4 1 2 Value example 14 FC LC RC LD RD 0 Description Unique attribute record identifier Feature code
13. raster data The record structure at this level may also be defined to be compatible with data in Levels 1 and 2 Ol Ordnance Meridian user guide chapter 6 v3 0 12 2000 Crown copyright 1 Survey Page 61 Ordnance Survey Meridian user guide chapter 6 v3 0 12 2000 Crown copyright Page 6 2 There are certain conventions used in this user guide which are 90 lt S gt lt 3S gt l Square brackets are placed around record names for example VOLHDREC A pair of braces denote field names for example REC_DESC is the Record Descriptor field A two digit number following square brackets denotes the record descriptor which uniquely identifies the record name between the brackets This is the space character ASCII code 32 This denotes three successive space characters The percentage character ASCII code 37 This denotes a repeating group ASCII code 124 Jackson structure The following diagrams are examples of Meridian 2 files and no fixed record sequence or relationship is implied Key one or more o selection SECHREC 07 POINT FEATURES POINT LINE NODE TEXT FEATURE FEATURE FEATURE FEATURE VOLHDREC 01 DATABASE VOLTERM 99 DBHREC 02 ATTDESC 40 FEATCLASS 05 SECTION SECTION BODY FEATURE LINE NODE FEATURES FEATURES TRANSFER SET VOLUME HA DATABASE BODY o CARTOGRAPHIC TEXT FEATURES
14. 1 Meridian user guide chapter 5 Oo Ordnance v3 0 12 2000 Crown copyright Survey Page 5 2 Chapter 6 NTF explained An overview of Meridian 2 in NTF This chapter gives a detailed breakdown of the data structure of Meridian 2 in NTF Meridian 2 data is supplied in the British Standard national format common to all Ordnance Survey s digital map data products namely NTF and is transferred in Level 3 as variable length records An overview of the data structure of a Meridian 2 data file is on page 6 2 The convention used for this diagram is in the industry standard adopted for Jackson Structured Programming JSP The British Standard for NTF stipulates the following for Level 3 This level supports a variety of data models that may include network data polygons semantic relationships and complex features for example a school consisting of its buildings boundaries and playing fields This level is designed for Transferring basic geometry and simple features through the use of geometry and feature records Relating basic geometrical and topological elements to one or more features through the use of chain polygon and complex line records e Combining features to form complex features through the use of collection and complex polygon records e Using text records both to relate text strings to features and cartographic output e Referencing and positioning external features for example
15. 14 Attribute Record ATTREC 14 for developed land use area points and or seeds 7 15 Attribute Record ATTREC 14 for cartographic name text 7 16 Attribute Record ATTREC 14 for railway links T 17 Attribute Record ATTREC 14 for railway station nodes 7 16 Attribute Record ATTREC 14 for water feature river small 7 19 Attribute Record ATTREC 14 for water area seeds 7 20 Attribute Record ATTREC 14 for administrative area points and or seeds 7 21 Attribute Record ATTREC 14 for gridded height point Tle Point Feature Record POINTREC 15 7 23 Node Record NODEREC 16 7 24 Two dimensional Geometry Record GEOMETRY1 21 associated with POINTREC 7 25 Two dimensional Geometry Record GEOMETRY 1 21 associated with LINEREC 7 26 Line Feature Record LINEREC 23 127 Attribute Description Record ATTDESC 40 7 28 Text Record TEXTREC 43 7 29 Text Position Record TEXTPOS 44 7 30 Text Representation Record TEXTREP 45 fot Comment Record COMMENT 90 7 02 Volume Terminator Record VOLTERM 99 7 33 Chapter 8 DXF explained 8 1 An overview of Meridian 2 in DXF 8 2 DXF 8 2 Structure of Meridian 2 in DXF 8 3 Line features 8 3 Area features 8 3 Name features 8 3 Drawing content and format 8 4 Coordinate system 8 4 Height 8 4 Layer names 8 4 Neatline 8 5 Grid 8 5 Grid values 8 5 Meridian 2 DXF layers 8 6 DXF footnotes 8 8 Chapter 9 DXF file structure for Meridian 2 9 1 General 9 1 Data structure 9 2 Header 9 3 Tables
16. 23 32 110 0000010000 YMAX 33 42 110 0000010000 XY_ACC 43 47 R5 2 00000 Z_ACC 48 52 R5 2 00000 SURV_DATE 53 60 DATE 00000000 LAST_AMND 61 68 DATE yyyymmdd COPYRIGHT 69 76 DATE yyyymmdd CONT_MARK 77 77 l1 0 EOR 78 78 Al Description 10 km by 10 km tile reference for example TQ24 lt 6S gt Rectangular Vector Five character coordinate fields to 1 metre Metres Default Not used Not used Not used X coordinates of south west corner of unit Y coordinates of south west corner of unit Not used Continuation record follows Record terminator Description Not used Not used Not used Date last amended Copyright date No further records Record terminator Record example 07TQ24 21000052000000100000000000000010000000520000000014000000000000001 00000000000000000000000000010000000001000000000000000000000020000901200009010 12345678901234567890123456789012345678901234567890123456789012345678901234567890 Template Oo Ordnance Meridian user guide chapter 7 v3 0 12 2000 Crown copyright 1 Survey Page 7 7 i Ordnance Survey Meridian user guide chapter 7 v3 0 12 2000 Crown copyright Page 7 8 Attribute Record ATTREC 14 for road links Field Position Format Value example REC_DESC 01 02 A2 14 ATT_ID 03 08 16 VAL_TYPE 09 10 A2 OD VALUE 11 23 A13 VAL_TYPE 24 25 A2 FC VALUE 26 29 14 VAL_TYPE a A2 LL VALUE se 15 VALUE TYPE A2 NP VALUE oe
17. A12 VALUE TYPE A2 PO VALUE ag A13 VAL_TYPE ie A2 PN VALUE 7 A DIVIDER eau Al VAL_TYPE a A2 RN VALUE ee A DIVIDER Li Al VAL_TYPE aa A2 TR VALUE Al CONT_MARK ate l1 0 or 1 EOR Li Al variable integer Description Unique ID for record Unique ID OSODR for link Feature code Length of link Number of parent OSODRs Parent OSODRs Road name Divider Road number Divider Trunk road indicator No further records or continuation record follows Record terminator Record example 140000010D03 3 8UHKO PLWAXFC3001LL00342NP02P001J945LPCABAXPOO1CB3HJ5 0VFWAPNCOMMERO OOCIAL STREET RNA315 T TRYO 12345678901234567890123456789012345678901234567890123456789012345678901234567890 Template Note PO records will be repeated NP number of times Continuation records will be used if necessary Oo Ordnance Meridian user guide chapter 7 v3 0 12 2000 Crown copyright 1 Survey Page 7 9 Meridian user guide chapter 7 oO Ordnance v3 0 12 2000 Crown copyright 1 Survey Page 7 10 Attribute Record ATTREC 14 for road nodes Field Position Format Value example Description REC_DESC 01 02 A2 14 ATT_ID 03 08 16 Unique ID for record VAL_TYPE 09 10 A2 OD VALUE 11 23 A13 Unique ID OSODR for node VAL_TYPE 24 25 A2 FC VALUE 26 29 14 Feature code VALUE TYPE La A2 NP VALUE a A Number of parent OSODRs VALUE TYPE ER A2 PO VALUE A Parent OSODRs
18. Crown copyright Page 6 19 Ordnance Survey Meridian user guide chapter 6 v3 0 12 2000 Crown copyright Page 6 20 Feature Type description Developed land use areas DLUA DLUA boundary Line DLUA seed Point DLUA node Point DLUA edge node Point Neat line Line Cartographic names Place name Point Station name Point Hydrology Water feature river small Line Water feature river medium Line Water feature river large Line Water feature hidden water Line Water feature aqueduct Line Water feature dark link Line Water feature canal Line Water feature lake Line Area water seed Point Water text Point Water feature node Point Area water node Point Area water edge node Point Water feature edge node Point Area water neat line Line Code 6300 6310 6720 6721 6801 6500 6551 6223 6224 6225 6230 6231 6232 6243 6255 6292 6552 6770 6771 6772 6773 6803 Attribute s FC FC PN DA FC FC FC FC TX FC TX FC WI PN FC WI PN FC WI PN FC WI PN FC WI PN FC WI PN FC WI PN FC WI PN FC WA FC TX FC FC FC FC FC Feature Type description Woodlands Woodland boundary Line Woodland seed Point Woodland node Point Woodland edge node Point Woodland neat line Line Height Gridded height Point Code 6664 6663 6750 6751 6802 6762 Attribute s FC FC FA TX FC FC FC FC HT Note Includes London borough and unitary authority areas
19. INSERT TEXT INSERT INSERT INSERT INSERT POLYLINE POLYLINE INSERT INSERT INSERT POLYLINE INSERT Colour WHITE WHITE WHITE WHITE WHITE WHITE CYAN CYAN BLUE BLUE BLUE RED CYAN BLUE RED WHITE RED RED RED RED CYAN MAGENTA RED GREEN GREEN MAGENTA YELLOW Block ME_FOOTNOTES SEEDPOINT CIRCLE CIRCLE CIRCLE CIRCLE CIRCLE SEEDPOINT CIRCLE Oo Ordnance Survey Meridian user guide chapter 8 v3 0 12 2000 Crown copyright Page 8 7 Oo Ordnance d Survey Meridian user guide chapter 8 v3 0 12 2000 Crown copyright Page 8 8 DXF footnotes The following footnotes are added as an insert BLOCK in the ENTITIES section of the DXF data file The positions of the footnotes are indicated in figure 8 1 Note 1 Note 2 Note 3 Note 4 Note 5 Note 6 Note 7 Note 8 Note 9 Top margin centrally aligned 1 750 ground metres Layer G8050571 Ordnance Survey Top margin centrally aligned 1 500 ground metres Layer G8050571 Meridian 2 data Lower left margin 500 ground metres Layer G8050571 Translation date dd Mmmmmmmmm CCYY Lower left margin 500 ground metres Layer G8050571 Tile reference number __ Lower left margin 500 ground metres Layer G8050571 Reproduced from Ordnance Survey Meridian 2 data with the permission of The Controller of Her Majesty s Stationery Office Crown Copyright CCYY Lower rig
20. These introductory records are followed by the data requested by the customer which are contained in the section The section consists of two parts 1 2 Section Header Record SECHREC this gives the National Grid coordinates of the section and on unformatted media inform the customer that a new section is starting Section body this comprises all the features within the section Ordnance survey Meridian user guide chapter 6 v3 0 12 2000 Crown copyright Page 6 9 Meridian user guide chapter 6 oO Ordnance v3 0 12 2000 Crown copyright Version management Each version and release of all Meridian 2 products are defined by a unique product version number and release number these are reflected in this user guide The product version number relates to the specification of the data being supplied and the release number relates to the release of the product The product version number takes the form xx yy where xx is the major product number and yy is the minor change number Thus version 02 00 would indicate that this is the major product version 02 and that the 00 indicates no minor amendment to the product specification The release number takes the form xx yy where xx is the sequential release within a year and yy is the year of the release Thus release 01 01 would indicate that this is the 1st data release in 2001 The product version number and the release number are speci
21. a value of Y Junction name JN attribute This attribute indicates the junction number of motorway junctions and the other classified roads at that junction The junction name is variable length text and is in the format M6J10A where M6 is the DETR road number and J10A indicates that this is the junction numbered 10A of the M6 If the junction has no junction number then that part of the junction name is not supplied There could be any number of roads at a junction therefore each classified road at that junction may be repeated in the junction name attribute An oblique character separates each road number and junction The following is an example of a junction name attribute M40J1 A40 A413 A4020 This attribute only applies to nodes If the node does not have a junction name then this attribute is not present Settlement name SN attribute This attribute defines the name of a location or settlement This name will be attached to the node which is closest to the position of the location or settlement Unique identifiers Unique identifiers are used to uniquely identify some features within Meridian 2 These are OSODR attribute defines the Ordnance Survey ROADS Database Reference OSODR This will uniquely identify any link or node within the national OSCAR dataset Railway and railway station identifiers These uniquely identify any railway link or railway station within the national Meridian 2 database Developed la
22. are on different layers In figure 3 1b Point A is a seed point with a feature code that identifies it as a developed land use area the seed point also carries its name attribute Bryncethin Point B is a coordinate junction between intersecting features in this case where a minor road intersects with the A4061 This is an example of a node Point C is a position where the A4061 in one layer crosses the developed land use area boundary in another layer There is no node at this point Some points and lines are common to more than one feature as in figure 3 1b Features between D E and G B F are overlapping features and are stored separately within each layer of data Tile Edge Nodes Links m om Seed points O Ordnance Survey Meridian user guide chapter 3 v3 0 12 2000 Crown copyright Page 3 3 oO Ordnance Meridian user guide chapter 3 v3 0 12 2000 Crown copyright Survey Page 3 4 Separate storage of overlapping features Figure 3 1c Roads Figure 3 1d Developed land use area P Q r V A4063 a ome So pos EX d ON i J Tile i E S I H Tile Edge iii i 4 la aA A s Q d D SN yo J a461 a 1 P as A y40e1 oa M o Nodes Links Nodes Seed point Links In figures 3 1c and 3 1d line D E is common to the minor road and the developed land use are
23. by means of a feature code FC A feature code is allocated when each feature is initially interpreted and captured from the map base In this way an A road is distinguished from a B road and other kinds of line feature by the feature code allocated to it Each feature is classified as belonging to a specific feature code These feature codes are listed in chapter 6 Each feature is classified as belonging to a specific feature layer These layers range in value from G8050570 to G8056801 see the AutoCAD publication Layer Naming Convention for CAD in the Construction Industry version 2 based upon guidelines in BS 1192 Part 5 Guide for structuring of computer graphic information These feature layers are listed in chapter 8 Attributes are stored as extended entity data A further four text feature codes for layout of footnotes are included These feature codes are listed in chapter 8 In order to display the attributes stored as extended entity data the following two scripts are required These two files Showeed Isp and Showeed dcl are contained in the EXE directory on the Ordnance Survey supplied CD ROM and should be placed in a directory in the AutoCAD preferences search string This should include the directory containing the map data files in DXF To utilise the scripts type the following at the AutoCAD command line prompt within a drawing session AutoCAD load showeed AutoCAD eedd Selecting a ma
24. concepts or instructions in a formalised manner suitable for communication interpretation or processing data capture The encoding of data In the context of digital mapping this includes map digitising direct recording by electronic survey instruments and the encoding of text and attributes by whatever means Ordnance Survey Meridian user guide appendix A v3 0 12 2000 Crown copyright Page A 3 Meridian user guide appendix A oO Ordnance v3 0 12 2000 Crown copyright Survey Page A 4 data format A specification that defines the order in which data is stored or a description of the way data is held in a file or record data model An abstraction of the real world which incorporates only those properties thought to be relevant to the application or applications at hand The data model would normally define specific groups of entities and their attributes and the relationship between these entities A data model is independent of a computer system and its associated data structures A map is one example of an analogue data model database An organised integrated collection of data stored so as to be capable of use in relevant applications with the data being accessed by different logical paths Theoretically it is application independent but in reality it is rarely so dataset An Ordnance Survey term for a named collection of logically related features arranged in a prescribed manner For exampl
25. device in variable length records with a maximum record length of 80 characters which includes CONT_MARK and EOR Record terminator EOR The end of record terminator is the percent ASCII 37 character for both formatted and unformatted media A transfer set normally equates to a single file except where continuation volumes are used when the transfer set exceeds the capacity of the media The data the customer receives is in one or more transfer sets Each transfer set starts with a Volume Header Record VOLHDREC and terminates with a Volume Terminator Record VOLTERM Supply of data on formatted media Data requested on CD is not blocked but is written directly to the output device The transfer set has one dataset and one section One or more transfer sets are put onto the medium A customer s order that is larger than the capacity of the medium is put onto two or more of that media Continuation volumes are only be used if a transfer set is larger than the capacity of the medium Formatted media transfer set less than media capacity 01 VOLUME HEADER RECORD 02 DATABASE HEADER RECORD 40 ATTRIBUTE DESCRIPTION RECORD 05 FEATURE CLASSIFICATION RECORD 7 0 SECTION HEADER RECORD Tile 1 data 99 VOLUME TERMINATION RECORD 7 01 VOLUME HEADER RECORD 02 DATABASE HEADER RECORD 40 ATTRIBUTE DESCRIPTION RECORD 05 FEATURE CLASSIFICATION RECORD 07 SECTION HEADER RECORD Tile 2 data 99 VOLUME TERMINATION RECORD 4 etc
26. district or unitary authority seed point There is no logical connection in the data between them and administrative units other than the same name attribute There is no explicit information to identify which links form the bounds of a particular area The left and right county and district pointers on links do not contain the name of the administrative area but refer to the seed point that has the administrative area name as its attribute The coastline follows the mean high water MHW up all estuaries to the normal tidal limit NTL Administrative areas are only shown down to MHW The administrative areas are adjusted to the coastline To maintain positional relationship features in this layer may be adjusted and fitted to roads and railways Changes to the local authorities of Wales and Scotland that have taken place between 1 April 1998 and May 1999 have been incorporated in the Meridian 2 database Local government in England is still under review although some counties have been concluded The operative dates for the new authorities extend from 1 April 1998 through to 1 May 1999 Hierarchical position 3 4 Developed land use areas Developed land use area features include cities towns villages and industrial commercial and business parks Link features enclose developed land use area features Such areas contain a seed point that identifies the enclosed area and carry a feature code and the associated developed land use area name
27. i Ordnance Meridian user guide chapter 7 v3 0 12 2000 Crown copyright 1 Survey Page 7 19 i Ordnance Survey Meridian user guide chapter 7 v3 0 12 2000 Crown copyright Page 7 20 Attribute Record ATTREC 14 for water area seeds Field Position Format REC_DESC 01 02 A2 ATT_ID 03 08 16 VAL_TYPE 09 10 A2 VALUE 11 14 14 VAL_TYPE 15 16 A2 VALUE 17 22 16 VAL_TYPE 23 24 A2 VALUE 25 A DIVIDER Fi A1 CONT_MARK 7 11 EOR Fe Al Note variable integer Record example 14000032FC6292WA053050PNULLSWATER 0 Value example 14 FC WA PN 0 or Description Unique attribute record identifier Feature code Unique water area seed identifier Water area name where applicable Divider No further records or continuation record follows Record terminator 12345678901234567890123456789012345678901234567890123456789012345678901234567890 Template Note The WI identifier in the record example is fictional and does not relate to Ullswater Attribute Record ATTREC 14 for administrative area points and or seeds Field Position Format Value example Description REC_DESC 01 02 A2 14 ATT_ID 03 08 16 Unique attribute record identifier VAL_TYPE 09 10 A2 FC VALUE 11 14 14 Feature code VAL_TYPE 15 16 A2 PI VALUE 17 22 16 Unique global seed identifier VAL_TYPE 23 24 A2 NM VALUE 25 A Admin area name DIVIDER pity Al Divider CONT_MARK ba 11 0 No further rec
28. is an attribute of a seed point in a woodland area Road number RN attribute This attribute defines the DETR road classification number for example M40 which relates to a link If a road is not classified then this attribute will not be present Trunk road TR attribute This attribute defines whether the link forms part of a trunk road If it is then the link will have a trunk road attribute with a value of Y and if it is not a trunk road then there will be no value in this field Line length LL attribute This attribute defines the length of the link in metres and will be present for all link records It is calculated from the planimetric coordinates making up the link and does not take into account the effect of slope The link length in all products refers to the length as recorded in the OSCAR database Number of parents NP attribute Because the data in the Meridian 2 road layer is generalised a feature may be derived from one or more basic OSCAR Asset Manager features Thus there may be a number of parent OSODR PO attributes associated with a single feature An additional attribute number of parents NP OSODRs is therefore supplied which defines the number of PO attributes that may be allocated to a feature NP attribute is supplied primarily to act as a counter to the number of parent OSODR attributes that are supplied for a particular feature PO and NP attributes apply to both links and nodes in the Meridian 2 road d
29. is not expressed in the data Other important data structure concepts include networks and polygons Networks are interconnecting features structurally related by means of an explicit point described as a node Between the nodes are series of non intersecting line segments described as links hence link and node see figure 2 1 This is of special interest in GIS where there may be a need to analyse the network in order to follow routes or to close polygons Proprietary GIS software can be used to build and maintain networks for linear features such as roads railways and so on and provides the functionality to store manage and manipulate this data The properties of Meridian 2 make it a suitable basis for users wishing to develop applications using Meridian 2 together with their own data As Meridian 2 is based on the National Grid there is a simple way of overlaying users own data provided the position is given within the National Grid The National Grid as it applies to Meridian 2 is explained in chapter 5 Figure 2 1 Link and node Points A and B are nodes as they intersect with other features The line A B is the link and in this example is made up of six individual line segments Polygons are continuous areas defined by sets of bounding closed lines These are implicit within the data but can be explicitly created with appropriate software Stored within recognisable polygons are seed points which hold i
30. line CONTINUOUS e DASHED e dashdot line DASHDOT e dotted line DOT dashed line Figure 9 5 Level 4 Key one or more o optional ALIGNMENT CODE GROUP LINETYPE NAME GROUP NUMBER OF DASH ITEMS GROUP LINETYPE DEFINITIONS STANDARD FLAGS GROUP TOTAL PATTERN LENGTH GROUP LINETYPE DESCRIPTION GROUP o DASH LENGTH GROUP LOS Ordnance Survey Meridian user guide chapter 9 v3 0 12 2000 Crown copyright Meridian user guide chapter 9 Oo Ordnance v3 0 12 2000 Crown copyright 2 CONTINUOUS 70 64 3 Solid Line 72 65 73 40 0 0 0 LTYPE 2 DASHED 70 64 OG N UI O ul LTYPE 2 DASHDOT 70 H H oO LTYPE DOT i Ordnance Meridian user guide chapter 9 v3 0 12 2000 Crown copyright 1 Survey Page 9 11 Oo Ordnance Meridian user guide chapter 9 A v3 0 12 2000 Crown copyright 73 2 0 25 0 0 49 0 25 0 ENDTAB Figure 9 6 Level 3 Key one or more o optional LAYER DEFINTIONS LAYER ENDTAB GROUP GROUP ITEM TYPE TABLE GROUP ENTRY Details of the Layer Table can be seen on page 8 6 ENDTAB GROUP COLOUR LINETYPE GROUP GROUP _ ols Ordnance Survey Meridian user guide chapter 9 v3 0 12 2000 Crown copyright Page 9 13 Meridian user guide chapter 9 oO Ordnance v3 0 12 2000 Crown copyr
31. of a link terminating Points may also be represented by symbols which may have attributes such as rotation and size polygon Polygons are a representation of areas A polygon is defined as a closed line or perimeter completely enclosing a contiguous space and made up of one or more links At least one node occurs on the perimeter of a polygon where the bounding link completes the enclosure of the area There may be many nodes connecting the bounding links of a polygon Links may be shared between polygons Polygons may wholly contain other polygons or be contained within other polygons Each may contain a single isolated node seed point which identifies the polygon polygon boundary The link or links which enclose a polygon projected into the horizontal plane polygon point See seed point positional accuracy The degree to which the coordinates define a point s true position in the world directly related to the spheroid projection on which the coordinate system is based precision The exactness with which a value is expressed whether the value be right or wrong record A set of related data fields grouped for processing recording format The logical and or physical levels of the protocol governing the laying down of data on the physical transfer medium rectangular coordinates Also known as X Y coordinates and as eastings and northings These are two dimensional coordinates which measure the position of any point relati
32. range of applications including initial planning and project work at a regional level Concepts of Meridian 2 are explained fully in chapter 2 Appropriate software is required to facilitate the customer s intended application The database has been derived from Ordnance Survey s existing large and small scales digital databases Ordnance Survey Meridian user guide chapter 1 v3 0 12 2000 Crown copyright Page 1 1 Meridian user guide chapter 2 Oo Ordnance v3 0 12 2000 Crown copyright Survey Page 1 2 Meridian 2 features Meridian 2 has feature codes which allow everything in the database to be allocated to a specific category users can group like features for search display and output routines Meridian 2 is defined as a limited link and node structure within each layer It contains points lines and nodes Nodes have pointers to lines that join at the node and similarly there are lines that enclose an area containing a point Some points are not contained within areas enclosed by lines e Department of Environment Transport and the Regions DETR road classification numbers are stored in attribute records and are applied to features such as roads Names applying to administrative areas and developed land use areas are also included in the attribute record of the appropriate point feature Annual updating of source databases ensures that high standards of currency and integrity are main
33. the BLOCKS section of the data file A list of these standard symbols is shown in chapter 8 Attributes are stored as extended entity data Ol Ordnance Meridian user guide chapter 3 v3 0 12 2000 Crown copyright 1 Survey Page 31 i Ordnance Survey Meridian user guide chapter 3 v3 0 12 2000 Crown copyright Page 3 2 Points and lines Real world geographic features are represented in the digital map data as structures of lines and points Each point or line has a geometric and attribute component The geometric component defines the positional characteristic of the feature and implicit relationships exist between points and lines based on relative position The attribute component defines the descriptive characteristics of the feature Points may exist independently of lines A diagrammatic example of a geometric structure is shown in figure 3 1a Figure 3 1a A geometric structure of points and lines Solid black grey and broken grey lines and associated points are on different layers Tile Edge Points e Lines Points and lines from the geometric structure become features when an attribute the feature code has been added for example developed land use area seed points are created from points or developed land use area boundaries from lines Figure 3 1b The same geometric structure as features Solid black greys and broken grey
34. 0 records indicates a repeating group The pair of fields VAL_TYPE and VALUE will repeat to specify all the attributes required It may be necessary to utilise a continuation record to specify all attributes Line Feature Record LINEREC 23 Field Position Format Value example Description REC_DESC 01 02 A2 23 LINE_ID 03 08 16 Unique line record identifier GEOM_ID 09 14 16 Pointer to GEOMETRY1 record NUM_ATT 15 16 12 01 ATT_ID 17 22 16 Pointer to ATTREC record CONT_ MARK 23 23 l1 0 No further records EOR 24 24 Al Record terminator Record example 23004804005369010053690 12345678901234567890123456789012345678901234567890123456789012345678901234567890 Template i Ordnance Meridian user guide chapter 7 v3 0 12 2000 Crown copyright _ Survey Page 7 27 Ordnance Survey Meridian user guide chapter 7 v3 0 12 2000 Crown copyright Page 7 28 Attribute Description Record ATTDESC 40 Field Position Format REC_DESC 01 02 A2 VAL_TYPE 03 04 A2 FWIDTH 05 07 A3 FINTER 08 12 A5 ATTNAME 13 A DIVIDER re Al FDESC ae A DIVIDER ae Al CONT_MARK pag 11 Note variable integer Record example for a fixed record 40P0013A13 1 2 Value example 40 001 999 or lt 3S gt format desc or A Attribute name Attribute description 0 PARENT OSODR Parent OSODR 0 3 4 Description Attribute mnemonic If fixed or if variable If fixed
35. 04804010048040 1 2 3 4 5 6 7 8 12345678901234567890123456789012345678901234567890123456789012345678901234567890 Template i Ordnance Meridian user guide chapter 7 v3 0 12 2000 Crown copyright Survey Page 7 23 i Ordnance Survey Meridian user guide chapter 7 v3 0 12 2000 Crown copyright Page 7 24 Node Record NODEREC 16 Field Position Format Value example REC_DESC 01 02 A2 16 NODE_ID 03 08 16 GEOM_ID 09 14 16 NUM_LINKS 15 18 14 gt 0 DIR g l1 1or2 GEOM_ID ee 16 ORIENT R4 1 LEVEL a l1 Oor1 1 CONT_MARK ie l1 0 or 1 EOR eu Al Note variable integer Record example 1600000800480400012004921226000 Description Unique node record identifier Pointer to GEOMETRY 1 record of point feature 1 for start of link or 2 for end of link Pointer to GEOMETRY 1 of link Bearing of first last segment of link clockwise from grid north not used for roads Link level at node roads only Link level at node for all other layers No further records or continuation record follows Record terminator 12345678901234567890123456789012345678901234567890123456789012345678901234567890 Template Notes indicates repeating group The pair of fields VAL_TYPE and VALUE will repeat to specify all the attributes required It may be necessary to utilise a continuation record to specify all attributes Two dimensional Geometry Record GEOMETRY1 21
36. 1 O0Meridian 02 00 20000901 00000000000 12345678901234567890123456789012345678901234567890123456789012345678901234567890 Template Feature Classification Record FEATCLASS 05 Field Position Format Value example Description REC_DESC 01 02 A2 05 FEAT_CODE 03 06 14 Contains four character feature code CODE_COM 07 16 A10 lt 10S gt Not used STCLASS 17 36 A20 lt 20S gt Not used FEATDES 372 A Feature description DIVIDER rF A1 Divider CONT_MARK net 11 0 No further records EOR i A1 Record terminator variable integer Record example 053000 Motorway 0 12345678901234567890123456789012345678901234567890123456789012345678901234567890 Template Oo Ordnance Survey Meridian user guide chapter 7 v3 0 12 2000 Crown copyright Page 7 5 i Ordnance Survey Meridian user guide chapter 7 v3 0 12 2000 Crown copyright Page 7 6 Section Header Record SECHREC 07 Record 1 Field Position Format Value example REC_DESC 01 02 A2 07 SECT_REF 03 12 A10 COORD_TYP 13 13 l1 2 STRUCT_TYP 14 14 l1 1 XYLEN 15 19 15 00005 XY_UNIT 20 20 l1 2 XY_MULT 21 30 R10 3 0000001000 ZLEN 31 35 15 00000 Z_UNIT 36 36 l1 0 Z_MULT 37 46 R10 3 0000001000 X_ORIG 47 56 110 Y_ORIG 57 66 110 Z_DATUM 67 76 110 0000000000 CONT_MARK 77 77 l1 1 EOR 78 78 A1 Record 2 Field Position Format Value example REC_DESC 01 02 A2 00 XMIN 03 12 110 0000000000 YMIN 13 22 110 0000000000 XMAX
37. 10 The OSODR for a feature will never be modified only created and deleted However there may be many changes to a feature with a specific OSODR during the lifetime of that OSODR allocation There are two reasons for changes These are the coordinates of the feature may move within a specified tolerance currently 3 m either side of a link 10 of its length and 5 m movement of any node or the attributes associated with a feature may change Any changes to these attributes will not affect the OSODR allocated to that feature The following attributes may change for link features date of survey of conversion feature code length of link road name road number and trunk road indicator The following attributes may change for node features direction of links at node feature code junction name number of links at node level of link at node and settlement name If a feature moves by more than the specified tolerance then the OSODR for the feature will be deleted and a new OSODR allocated to that feature If a feature is deleted from the OSCAR product and the ROADS database then the OSODR allocated to that feature will cease to exist and will not be reallocated Link level at node The level field in Node Record 16 indicates for roads the relative height relationship between intersecting links at a node It does not relate to ground surface level If a road over a bridge can be accessed the
38. 33 Meridian user guide chapter 7 oO Ordnance v3 0 12 2000 Crown copyright H Survey Page 7 34 Chapter 8 DXF explained The purpose of this chapter and chapter 9 is to e Provide a brief description of the presentation of Meridian 2 in the DXF transfer format e Data Exchange Format DXF conforming to AutoCAD release 12 with extended entity data As part of this description data structure diagrams are used to give greater explanation where necessary Provide Licensed Partners with as much detail as necessary to enable Meridian 2 files in DXF to be easily understood and processed by application software The term data structure used in these chapters refers to the organisation and sequence of the records in the data file and not to the geographical topology of the data These chapters should be read in conjunction with chapters 1 2 and 3 which describe the content of Meridian 2 This chapter describes the representation of Meridian 2 in Ordnance Survey s implementation of DXF Meridian 2 is supplied to the product specification Meridian_02 00 Ol Ordnance Meridian user guide chapter 8 v3 0 12 2000 Crown copyright 1 Survey Page 81 i Ordnance Survey Meridian user guide chapter 8 v3 0 12 2000 Crown copyright Page 8 2 An overview of Meridian 2 in DXF DXF Meridian 2 is available in DXF conforming to AutoCAD release 12 using extended entity data to stor
39. 9 7 Blocks 9 16 Entities Section 9 18 End of File Group 9 25 Appendix A Glossary A 1 Appendix B Product performance report form B 1 Ol Ordnance Meridian user guide contents v3 0 12 2000 Crown copyright survey Contents page 5 Meridian user guide contents Oo Ordnance v3 0 12 2000 Crown copyright Survey Contents page 6 Chapter 1 Introduction This user guide is designed to enable users to make effective use of Meridian 2 and contains all the information you will need This chapter and chapter 2 provide an introduction to Meridian 2 and illustrate potential applications Chapter 3 contains details of the components of the data Please refer to the Glossary if you are unfamiliar with the terms used All aspects of Meridian 2 discussed in this user guide relate to Meridian 2 in both BS 7567 NTF v2 0 and DXF AutoCAD Release 12 formats If the two format versions differ in their treatment of a particular aspect the specific differences will be stated Icons as shown below will be used to denote these differences For convenience BS 7567 NTF v2 0 level 3 is referred to as NTF in this user guide Data Exchange Format DXF is referred to as DXF in this user guide Format information on the Meridian 2 data is contained in chapters 3 and 8 Ordnance Survey s Meridian 2 provides a comprehensive national database of geographic spatial information designed to support a wide
40. Attribute Record ATTREC 14 for railway station nodes Field Position Format Value example Description REC_DESC 01 02 A2 14 ATT_ID 03 08 16 Unique attribute record identifier VAL_TYPE 09 10 A2 FC VALUE 11 14 14 Feature code VAL_TYPE 15 16 A2 SI VALUE 17 29 A13 Unique railway station identifier VAL_TYPE 30 31 A2 PN VALUE 32 A Station name DIVIDER Al Divider CONT_MARK bi 11 0 No further records or 1 or continuation record follows EOR Fe A1 Record terminator Note variable integer Record example 14000003FC6155S14169010274901PNSandling Station 0 12345678901234567890123456789012345678901234567890123456789012345678901234567890 Template Attribute Record ATTREC 14 for water feature river small Field Position Format Value example Description REC_DESC 01 02 A2 14 ATT_ID 03 08 16 Unique attribute record identifier VAL_TYPE 09 10 A2 FC VALUE 11 14 14 Feature code VAL_TYPE 15 16 A2 WI VALUE 17 29 A13 Unique water feature identifier VAL_TYPE 30 31 A2 PN VALUE 32 A River name optional DIVIDER a Al Divider CONT_MARK A 11 0 No further records or or continuation record follows EOR Re A1 Record terminator Note variable integer Record example 14000003FC6223WI161690502790901PNRiver Lydden 0 12345678901234567890123456789012345678901234567890123456789012345678901234567890 Template Note The WI identifier in the record example is fictional and does not relate to River Lydden
41. C_DESC 01 02 A2 ATT_ID 03 08 16 VAL_TYPE 09 10 A2 VALUE 11 14 14 CONT_MARK 15 15 l1 EOR 16 16 A1 Value example 14 FC 0 Description Unique attribute record identifier Feature code No further records Record terminator Attribute Record ATTREC 14 for developed land use area links Field Position Format REC_DESC 01 02 A2 ATT_ID 03 08 16 VAL_TYPE 09 10 A2 VALUE 11 14 14 CONT_MARK 15 15 l1 EOR 16 16 Value example 14 FC 0 Description Unique attribute record identifier Feature code No further records Record terminator Attribute Record ATTREC 14 for developed land use area points and or seeds Field Position Format Value example Description REC_DESC 01 02 A2 14 ATT_ID 03 08 16 Unique attribute record identifier VAL_TYPE 09 10 A2 FC VALUE 11 14 14 Feature code VAL_TYPE 15 16 A2 DA VALUE 17 29 A13 Unique developed land use area seed identifier VAL_TYPE 30 31 A2 PN VALUE 32 A Developed land use area name DIVIDER gu A1 Divider CONT_MARK A 11 0 No further records or or continuation record follows EOR A1 Record terminator Note variable Record example 14000032FC6310DA4418200463301PNGrafton 0 1 2 3 4 5 6 7 8 12345678901234567890123456789012345678901234567890123456789012345678901234567890 Template ol Ordnance Meridian user guide chapter 7 v3 0 12 2000 Crown copyright 1 Survey Page 7 15 i Ordnance Survey Meri
42. E_ID 43 Tile id NT86 Feature layers This section contains a list of all the valid features used with Meridian 2 The list contains a description of each feature its feature type its feature code FC and a list of the attributes other than FC which can be associated with that feature The list is segmented by feature layer Note all features carry the attribute FC as the feature code Feature Type Code Attribute s description Roads Motorway Line 3000 FC LL NP OD PO RN TR PN A road Line 3001 FC LL NP OD PO RN TR PN B road Line 3002 FC LL NP OD PO RN TR PN Minor road Line 3004 FC LL NP OD PO RN TR PN Road node Point 3500 FC NP OD PO JN RT SN Road edge node Point 3501 FC NP OD PO JN RT SN Railways Railway Line 6140 FC RI Tunnelled railway Line 6142 FC RI Railway station Point 6155 FC SI PN Railway node Point 6730 FC Railway edge node Point 6731 FC Administrative areas and coastline County boundary Line 6401 FC LC RC District boundary Line 6403 FC LD RD County district boundary Line 6405 FC LC RC LD RD Neat line Line 6800 FC LC RC LD RD County seed Point 6411 FC PI NM District seed Point 6415 FC Pl NM Boundary node Point 6710 FC Boundary edge node Point 6711 FC Coastline Line 6200 FC LC RC LD RD Coastline node Point 6740 FC Coastline edge node Point 6741 FC Ordnance Survey Meridian user guide chapter 6 v3 0 12 2000
43. Left county pointer to seed optional Right county pointer to seed optional Left district pointer to seed optional Right district pointer to seed optional No further records Record terminator 6 7 8 12345678901234567890123456789012345678901234567890123456789012345678901234567890 Template Attribute Record ATTREC 14 for administrative area points and or seeds Field Position Format Value example Description REC_DESC 01 02 A2 14 ATT_ID 03 08 16 Unique attribute record identifier VAL_TYPE 09 10 A2 FC VALUE 11 14 14 Feature code VAL_TYPE 15 16 A2 PI VALUE 17 22 16 Unique global seed identifier VAL_TYPE 23 24 A2 NM VALUE 25 A Administrative area name DIVIDER pity Al Divider CONT_MARK ba 11 0 No further records or 1 or continuation record follows EOR Re A1 Record terminator Note variable integer Record example 14000032FC6411PI043050NMHAMPSHIRE COUNTY 0 1 2 3 4 5 6 7 8 12345678901234567890123456789012345678901234567890123456789012345678901234567890 Template ol Ordnance Meridian user guide chapter 7 v3 0 12 2000 Crown copyright Survey Page 7 13 i Ordnance 1 Survey Meridian user guide chapter 7 v3 0 12 2000 Crown copyright Page 7 14 Attribute Record ATTREC 14 for nodes administrative areas developed land use area coastline and railway hydrology and woodlands and or edge nodes all layers Field Position Format RE
44. Line Boundary Line Landranger Strategi Strategi Strategi Land Form PANORAMA Source scales 1 1250 1 2500 and 1 10 000 1 1250 1 2500 and 1 10 000 1 10 000 1 10 000 1 10 000 1 50 000 1 250 000 1 250 000 1 250 000 1 50 000 Meridian user guide chapter 4 v3 0 12 2000 Crown copyright Page 4 1 Oo Ordnance Survey Meridian user guide chapter 4 v3 0 12 2000 Crown copyright Page 4 2 Currency Meridian 2 data is derived from the latest available versions of Ordnance Survey s databases The Meridian 2 dataset will be refreshed annually commencing in January 2002 The large and small scales databases are controlled by the revision criteria for topography that are defined by Ordnance Survey for the various geographical areas Accuracy and resolution The resolution of the data supplied is 1 metre Meridian 2 data retains the same accuracy as the source data during its capture However it is not possible to calculate meaningful accuracy criteria for these data due to different source databases OSCAR Route Manager has a 20 m filter applied to the centre line which is supplied to 1 m resolution The 20 m filter does not affect the positional accuracy of node points During the updating of OSCAR data there is a comparison buffer created around the existing OSCAR data to detect change This buffer is set to 3 m either side of a feature 5 m at each end and 10 of the length
45. REEN GREEN GREEN GREEN BLUE GREEN GREEN GREY GREY GREEN GREEN GREY Block CIRCLE small CIRCLE small CIRCLE CIRCLE small CIRCLE small SEEDPOINT SEEDPOINT CIRCLE CIRCLE CIRCLE CIRCLE DLUASEED CIRCLE CIRCLE Layer name G8056500 G8056551 G8050575 G8050571 G8050572 G8050573 G8056223 G8056224 G8056225 G8056230 G8056231 G8056232 G8056243 G8056255 G8056292 G8056552 G8056770 G8056771 G8056772 G8056773 G8056803 G8056664 G8056750 G8056663 G8056751 G8056802 G8056762 Feature name Place name Station name Default Footnotes Grid lines and values Grid values River small River medium River large Hidden water Aqueduct Dark link Canal Area water lake Area water seed Water text Water feature node Area water node Area water edge node Water feature edge node Area water neat line Woodland boundary Woodland boundary node Woodland seed Woodland tile edge node Woodland tile edge polygon Gridded height Linetype STANDARD STANDARD CONTINUOUS STANDARD CONTINUOUS STANDARD CONTINUOUS CONTINUOUS CONTINUOUS CONTINUOUS CONTINUOUS CONTINUOUS CONTINUOUS CONTINUOUS CONTINUOUS STANDARD DOT DOT DOT DOT CONTINUOUS CONTINUOUS DOT CONTINOUS DOT CONTINUOUS DOT Line ND 32 CO ND oH Entity TEXT TEXT POLYLINE INSERT LINE TEXT TEXT POLYLINE POLYLINE POLYLINE POLYLINE POLYLINE POLYLINE POLYLINE POLYLINE
46. a INSERT entities these consist of INSERT entity type group Layer name group Block name group X coordinate group Y coordinate group X scale factor Y scale factor Orientation group LINE entities these consist of LINE entity type group Layer name group Start X coordinate group Start Y coordinate group End X coordinate group End Y coordinate group Attribute number 0 8 2 10 20 41 optional 42 optional 50 optional if 0 RAR a a a a RUSSES c POLYLINE entities these consist of e POLYLINE entity type group 0 e Layer name group 8 Vertices follow flag group 66 e Polyline flags group 70 optional e A number of VERTEX entities shown on the next page e SEQEND group 0 d VERTEX entities these consist of VERTEX entity type group Layer name group X coordinate group 1 Y coordinate group Z coordinate group e TEXT entities these consist of TEXT entity type group 0 Layer name group 8 X coordinate group 10 Y coordinate group 20 Text height group 40 Text string group Justify type group Justify type group Orientation group Text style group Align X group Align Y group optional if 0 73 optional if 0 50 optional if 0 optional only present if Justify type group is present and has a value of 2 only present if Justify type group is present and has a value of 2 _ ols Ordnance S
47. a boundary and the geometry of each feature is stored separately Figure 3 1e Administrative areas and coastline Tile Edge Nodes e Seed point O Links In figures 3 1c and 3 1e line G B F is common to the A4061 the minor road and administrative area boundary and the geometry of each feature is stored separately Feature position The geometry of map features is defined in terms of coordinates All coordinates used in Meridian 2 are based on the National Grid coordinate referencing system and are quoted to a resolution of 1 metre The National grid as it applies to Meridian 2 is explained more fully in chapter 5 i Ordnance Meridian user ee chapter 3 4 v3 0 12 2000 Crown copyright Survey Page 3 5 Meridian user guide chapter 3 oO Ordnance v3 0 12 2000 Crown copyright Survey Page 3 6 Feature attribute data An attribute is the descriptive characteristic of a feature that is a non spatial element The geometry of the points and lines within the data would be meaningless to the user unless they are assigned some distinguishing property In Ordnance Survey map data terms an attribute can be a feature code in NTF these are numeric codes for example 3000 or a distinctive name or number for example Birmingham or M40 Attribute codes relevant to NTF are listed and described within chapter 6 but an overview is given below Feature codes Each feature is classified
48. ance Survey Meridian user guide appendix A v3 0 12 2000 Crown copyright Page A 11 Meridian user guide appendix A Oo Ordnance v3 0 12 2000 Crown copyright structured data Data within which collections of features of any type form objects Topographically structured data also contains topological information defining the relationships between features and objects terminator A character character string field or record used to signal the end of a record section volume or database text coordinates Each text feature has a start of text coordinate which is digitised text feature A free standing text string in the digital data describing a feature or particular instance of a feature for example Factory or Acacia Avenue text height The height at which a text string is intended to be plotted out at the nominal map scale This information is included in the feature header of the text feature text position See text coordinates Also known as original digitising position tile Broadly synonymous with digital map file it implies evenly sized map sheet units topographic database A database holding data relating to physical features and boundaries on the Earth s surface topography Topography is the study of the physical features of the Earth A topographic map s principal purpose is to portray and identify the features of the Earth topology The study of the properties of a geometric
49. area name for example Great Ayton Station then the points will carry a railway station name Node attributes will also be shown as cartographic station names To maintain positional relationship features in this layer may be adjusted and fitted to the roads Hierarchical position 2 Ol Ordnance Meridian user guide chapter 3 v3 0 12 2000 Crown copyright 1 Survey Page 3 15 Meridian user guide chapter 3 oO Ordnance v3 0 12 2000 Crown copyright 1 Survey Page 3 16 3 Administrative areas and coastline Administrative areas include information for unitary authority areas for Scotland Wales county district and London borough boundaries for England Figure 3 4 Hierarchical relationship of boundaries for England Line A is a county and district or London borough boundary Line B is a district or London borough boundary Each link for an administrative area carries a feature code and the administrative level associated with the left and right sides of that link This also applies to coastline but only to the landside of the coastline that is no administrative area information is added to the seaward side Each administrative area contains a seed point that identifies the enclosed area and carries a feature code and the associated administrative area name Separate areas of the same administrative unit carry seed points with different identifiers Offshore islands carry a county and
50. associated with POINTREC Field Position Format Value example Description REC_DESC 01 02 A2 21 GEOM_ID 03 08 16 Unique geometry record identifier GTYPE 09 09 l1 1 Point feature NUM_COORD 10 13 14 0001 Point has one coordinate pair X_COORD 14 18 15 X co ordinate Y_COORD 19 23 15 Y co ordinate QPLAN 24 24 Al lt S gt Not used CONT_MARK 25 25 l1 0 No further records EOR 26 26 Al Record terminator Record example 21000031100011564044030 0 1 2 3 4 5 6 7 8 12345678901234567890123456789012345678901234567890123456789012345678901234567890 Template i Ordnance Meridian user guide chapter 7 v3 0 12 2000 Crown copyright Survey Page 7 25 Meridian user guide chapter 7 oO Ordnance v3 0 12 2000 Crown copyright Survey Page 7 26 Two dimensional Geometry Record GEOMETRY1 21 associated with LINEREC Field Position Format Value example Description REC_DESC 01 02 A2 21 GEOM_ID 03 08 16 Unique geometry record identifier GTYPE 09 09 l1 2 Line feature NUM_COORD 10 13 14 Number of coordinate pairs in range 0002 9999 X COORD 14 18 15 X coordinate Repeated until NUM_COORD has been transferred Y_COORD 19 23 15 Y coordinate Repeated until NUM_COORD has been transferred QPLAN 24 24 Al lt S gt Not used CONT_MARK tg l1 0 No further records or1 or continuation record follows EOR a Al Record terminator Notes variable integer This record may contain many CONTINUATION 0
51. at any plotted or printed output contains the required copyright acknowledgement User guide copyright Trademarks This document is Crown copyright 2000 All rights reserved It is supplied with Meridian 2 to allow you to make effective use of the data Any part of it may be copied for your own business use Business use is defined as actions related to business decision making or as part of day to day operations associated with the running of a business No part of this document may be copied or incorporated in products services or publications you generate for onward sale or as free promotional or support material without the prior written permission of Ordnance Survey Ordnance Survey the OS Symbol Land Form PANORAMA Land Line Landranger OSCAR OSCAR Asset Manager OSCAR Route Manager and Strategi are registered trademarks and Boundary Line and Meridian are trademarks of Ordnance Survey the national mapping agency of Great Britain AutoCAD and Autodesk are registered trademarks and DXF is a trademark of Autodesk Inc Helvetica is a registered trademark of Linotype AG and or its subsidiaries Univers is a registered trademark of Haas sche Schrifigiesserei Ordnance Survey Meridian user guide v3 0 12 2000 Crown copyright SV eh Soon 1 Survey Chapter 1 Chapter 2 Introduction Meridian 2 features Applications of Meridian 2 What you need to use Meridian 2 Computer hardware Computer soft
52. ata In the Meridian 2 road data all links at roundabouts and complex junctions will have been reduced to a single node point Therefore the parent OSODRs referenced as attributes of node records may refer to both nodes and links in OSCAR Asset Manager OSODR attribute This attribute defines the Ordnance Survey ROADS Database Reference OSODR This will uniquely identify any link or node within the national OSCAR dataset The OSODR will be used as the unique identifier for each link and node rather than the NTF identifiers The NTF identifiers will be unique within each tile that is supplied but will not be maintained between supplies A road object is part of a road between nodes junctions uninterrupted by tile or map edges An OSODR refers not just to a single link but may refer to many links that make up a road object which may be chained together across tile edges Thus on adjoining tiles there may be two or more links with the same OSODRs This attribute applies to links and nodes It will be present for all features An OSODR has been assigned to all existing features links and nodes in the OSCAR database Any features which are new to ROADS after the initial allocation will be assigned an OSODR when they are loaded to the database i Ordnance Meridian user guide chapter 3 v3 0 12 2000 Crown copyright Ordnance Survey Meridian user guide chapter 3 v3 0 12 2000 Crown copyright Page 3
53. atic view of the data structure with a preceding outline description of that part of the data structure 2 Detailed examples of the record sequence and contents of the data structure A diagram of the record group precedes each example Ol Ordnance Meridian user guide chapter 9 v3 0 12 2000 Crown copyright 1 Survey Page 91 reg Meridian user guide chapter 9 v3 0 12 2000 Crown copyright Page 9 2 Data structure The following diagrams figures 9 1 9 14 represent the data structure of DXF Where one element of a figure is the starting point for another figure this is indicated beneath the relevant box For details of the specification for the DXF group see the AutoCAD Release 12 reference manual Figure 9 1 Level 1 Key one or more o optional DXF FILE 0 o 0 HEADER TABLES BLOCKS ANTTES SECTION SECTION SECTION Figure 9 2 Figure 9 3 Figure 9 9 Figure 9 11 Header The header will be constructed as follows with only those fields being supplied Figure 9 2 Level 2 Key 0 one or more SECTION o optional HEADER SECTION START HEADER VARIABLE GROUP SEQUENCE END SEC GROUP SECTION HEADER HEADER The header must be structured in the following order 0 SECTION 2 HEADER 9 SACADVER AutoCAD drawing database version number al AC1009 This indicates Release 11 o
54. coordinates or if there are only two coordinate pairs from the start to the end of the line The end of line bearing indicated by a 2 in the DIR field is the bearing of the last segment of the line The direction is from the end of the feature to the last minus one pair of coordinates Attribute codes Attribute Codes provide supplementary information on a feature providing such qualifying information as feature code feature name orientation and so on In NTF the structure of user defined attributes are described in the Attribute Description Record ATTDESC The actual attribute detail of a record is written in the Attribute Record ATTREC Ol Ordnance sev user guide chapter 6 v3 0 12 2000 Crown copyright Survey Page 6 15 Ordnance Survey Meridian user guide chapter 6 v3 0 12 2000 Crown copyright Page 6 16 Attributes which are used in the supply of Meridian 2 data are FC OD RN TR RT JN LC RC LD RD PI DA PN RI SN SI NM TX FA WA WI HT Feature code contains the numeric feature code of the feature OSODR a unique identifier for links and nodes on road features Road number DETR route number Trunk road indicator Roundabout indicator Junction name the name of a road junction Left county boundary indicator Right county boundary indicator Left district boundary indicator Right district boundary indicator Global ID a unique identif
55. dentifier when the database is refreshed The unique identifier for a feature will never be modified only created and or deleted If a feature is deleted from the Meridian 2 database then the unique identifier allocated to that feature will cease to exist Feature layer descriptions The feature codes which appear in Meridian 2 within each layer are detailed in chapter 6 The individual layers are described below Note Names or numbers appear in all layers as attributes The roads layer is the first hierarchical layer the other layers will be manipulated to fit in the following 1 7 hierarchical order 1 Roads Motorways major and minor roads are represented in the data Complex junctions are collapsed to single nodes and multi carriageways to single links To avoid congestion some minor roads and cul de sacs less than 200 m are not represented in the minor road feature description of the data Private roads and tracks are not included Hierarchical position 1 2 Railways All railway stations open to passengers and single track passenger lines are represented A railway intersection consists of links and a node but where railways cross at different levels links are not broken Links and nodes carry a feature code If the station name differs from the name of the built up area on Ordnance Survey s large scale data for example New Street Station in Birmingham or if the railway station name is not associated to any built up
56. dian user guide chapter 7 v3 0 12 2000 Crown copyright Page 7 16 Attribute Record ATTREC 14 for cartographic name text Field Position Format REC_DESC 01 02 A2 ATT_ID 03 08 16 VAL_TYPE 09 10 A2 VALUE 11 14 14 VAL_TYPE 15 16 A2 VALUE FE A DIVIDER us Al CONT_MARK 11 EOR yey Al Note variable Record example 14000012FC6500TXANDOVER 0 Value example 14 FC TX Oor 1 or Description Unique attribute record identifier Feature code Text string Divider No further records or continuation record follows Record terminator 12345678901234567890123456789012345678901234567890123456789012345678901234567890 Template Attribute Record ATTREC 14 for railway links Field Position Format Value example Description REC_DESC 01 02 A2 14 ATT_ID 03 08 16 Unique attribute record identifier VAL_TYPE 09 10 A2 FC VALUE 11 14 14 Feature code VAL_TYPE 15 16 A2 RI VALUE 17 29 A13 Unique railway link identifier CONT_MARK 30 30 11 0 No further records EOR 31 31 A1 Record terminator Record example 14000002FC6140RI41842002735110 1 2 3 4 5 6 y 8 12345678901234567890123456789012345678901234567890123456789012345678901234567890 Template ol Ordnance Meridian user guide chapter 7 v3 0 12 2000 Crown copyright 1 Survey Page 7 17 i Ordnance Survey Meridian user guide chapter 7 v3 0 12 2000 Crown copyright Page 7 18
57. e chapter 8 v3 0 12 2000 Crown copyright Page 8 6 Meridian 2 DXF layers Layer name G8053000 G8053001 G8053002 G8053004 G8053500 G8053501 G8056140 G8056142 G8056155 G8056730 G8056731 G8056401 G8056403 G8056405 G8056800 G805641 1 G8056415 G8056710 G8056711 G8056200 G8056740 G8056741 G8056300 G8056310 G8056720 G8056721 G8056801 Feature name Motorway A road B road Minor road Road node Road edge node Railways Tunnelled railway Station Railway node Railway edge node County boundary District boundary London borough unitary authority County district London borough unitary authority boundary Boundary neat line County seed District seed Boundary node Boundary edge node Coastline Coastline node Coastline edge node DLUA boundary DLUA seed DLUA node DLUA edge node DLUA neat line Linetype CONTINUOUS CONTINUOUS CONTINUOUS CONTINUOUS DOT DOT CONTINUOUS DASHED DOT DOT DOT DASHDOT DASHED DASHDOT CONTINUOUS CONTINUOUS CONTINUOUS DOT DOT CONTINUOUS DOT DOT CONTINUOUS CONTINUOUS DOT DOT CONTINUOUS Entity POLYLINE POLYLINE POLYLINE POLYLINE INSERT INSERT POLYLINE POLYLINE INSERT INSERT INSERT POLYLINE POLYLINE POLYLINE POLYLINE INSERT INSERT INSERT INSERT POLYLINE INSERT INSERT POLYLINE INSERT INSERT INSERT POLYLINE Colour BLUE RED ORANGE WHITE GREEN GREEN WHITE WHITE RED GREEN GREEN GREEN GREEN GREEN GREEN G
58. e all water features A dataset has more internal structure than a layer and is related to another dataset only by position DDS Digital Data Storage density A measure of the number of units of data held on a stated length of storage surface detached part A term applying to a part of a local government or parliamentary area which is completely surrounded by other local government or parliamentary areas and is not connected to the parent area by direct access on the ground digital Data which is expressed as numbers digits in computer readable form is said to be digital digital map Any map sold by Ordnance Survey or its agents in any form that is on computer readable media or as hard copy on paper and or film or microfilm produced mainly or wholly using computerised means digital map data The digital data required to represent a map The data includes not only map detail but also feature header data map header data and management data digitising The process of converting analogue maps and other sources to a computer readable form This may be point digitising where points are only recorded when a button is pressed on a cursor or stream digitising where points are recorded automatically at preset intervals of either distance or time as the cursor is traced along a map feature distinctive name A text feature consisting of text string s which form s a proper name DXF Data Exchange Format A proprietary data forma
59. e attributes The transfer format is that defined by the NEDO Working Party for the exchange of two dimensional drawings in the construction industry An overview of the data structure of a Meridian 2 file in DXF is shown below Key one or more o optional HEADER SECTION TABLES SECTION DXF FILE BLOCKS SECTION ENTITIES SECTION END OF FILE GROUP Structure of Meridian 2 in DXF Meridian 2 has a limited link and node data structure within this structure a feature may be a name a point or a line or series of lines forming a coherent unit Each feature is free standing that is its topological relationship to any other feature is not expressed in the data Features are classified by type and each type is placed in a separate DXF layer Line features A feature is a subjective entity that is so long as the constituent lines are of the same description layer a feature need not fully describe a logical piece of detail The extent of a feature is determined by digitising conventions and does not always coincide with the topology Each linear feature is composed of a string of XY coordinate pairs implicitly joined by straight lines The colour and line weights of some layers may differ when DXF is used with certain software packages Area features Area features are not defined within vector link and node data Features that might be thought of as area features are treated in the data as l
60. ee the AutoCAD publication Layer Naming Convention for CAD in the Construction Industry version 2 which is based upon the guidelines laid down in BS 1192 Part 5 Guide for structuring of computer graphic information Each layer name is an eight character string The first four characters relate to the AUG Autodesk system with G GIS as the source of the information and 800 899 as the part code This product is G805 The remaining four digits relate to existing Ordnance Survey digital map data in their own NTF system and are leading zero filled For example G8055310 Motorways Neatline Neatlines around the extent of the map data are added as lines in the ENTITIES section layer name G8050572 Grid A grid is added as lines in the ENTITIES section layer name G8050572 The grid is created by the translator and therefore must be specified before the translation takes place Grid values Full 100 000 metre National Grid easting and northing values followed by an m are added as text strings in the ENTITIES section layer name G8050573 at each corner of the map extent either horizontal or vertical to read from the lower left corner of the tile Intermediate grid values are shown as multiples of 1000 metres from the nearest 100 km National Grid layer name G8050572 These are horizontal i Ordnance Meridian user guide chapter 8 v3 0 12 2000 Crown copyright Oo Ordnance Survey Meridian user guid
61. er database and appropriate applications software geometric structure The ground is modelled in the data as a series of lines and points gigabyte Gb 1 073 741 824 bytes a measure of data storage capacity grid The planimetric frame of reference For example the National Grid hard copy A print or plot of output data on paper or some other tangible medium junction A connection between two or more links at a common node kilobyte Kb 1024 bytes a measure of data storage capacity layer A subset of digital map data selected on a basis other than position For example one layer might consist of all features relating to roads and another to railways line A series of connected coordinated points forming a simple feature with homogeneous attribution line feature The spatial abstraction of an object in one dimension Lines may intersect with other lines They are defined as a series of two or more coordinates and may be curved or straight Curved lines consist of a series of very short straight line segments Lines may be concurrent with other lines under certain conditions As an object abstraction a line has no width line segment A vector connecting two coordinated points linear feature Map feature in the form of a line for example road centrelines that may or may not represent a real world feature Ordnance Survey Meridian user guide appendix A v3 0 12 2000 Crown copyright Page A 7 M
62. er format used boundary A boundary is the limit of a pre defined and established area whose limit is determined by one or more lines for example county area boundary and developed land use area boundary byte A unit of computer storage of binary data usually comprising 8 bits equivalent to a character Hence megabyte Mb and gigabyte Gb CAD Computer aided design cartography The organisation and communication of geographically related information in either graphic or digital form It can include all stages from data acquisition to presentation and use character A distinctive mark an inscribed letter one of a set of writing symbols character string A one dimensional array of charcters held either in memory or in another storage medium coding Allocation of a feature code to a feature being created from constituent construction data points and or segments with optional linking to an existing feature of the same feature code compact disc read only memory CD ROM A data storage medium A 12 cm disc similar to an audio CD Ordnance Survey uses the writable CD a WORM write once read many device The digital bits are encoded into a vegetable dye and once written cannot be erased by overwriting with subsequent data Laser reads the disc continuation mark A logical record may contain more data than can be held in a single physical record The physical record contains a continuation mark the penultimate characte
63. er might consist of all features relating to roads and another to railways The first and last coordinate pairs in a line correspond exactly with the start or end coordinates of any adjoining line s A line cannot cross from one tile 10 km by 10 km square to the next it is split on the tile edge see Unique identifiers All linear features are continuous Cartographic gaps are closed during the digitising process Coordinates Coordinate values and the number of coordinate pairs in a feature are transferred in the GEOMETRY1 NTF record All coordinates within the data are expressed as strings of five numeric characters Leading zeros are present to complete the five characters All coordinates are measured from the local origin which is the south west corner of the tile To convert coordinate data to full National Grid coordinates add the coordinates of the feature to those of the south west corner of the tile The south west corner coordinates are contained within the X_ORIG and Y_ORIG fields of the Section Header Record SECHREC 07 Bearings Bearings are transferred in the ORIENT field of the Node Record NODEREC Bearings are National Grid bearings in degrees measured clockwise from grid north The start of line bearing indicated by a value of 1 in the DIR field of the Node Record NODEREC is the bearing of the first segment of the line The direction is from the start of the line to the next pair of
64. eridian user guide appendix A oO Ordnance v3 0 12 2000 Crown copyright Survey Page A 8 link Links are the representation of line features They are made up of one or more consecutive non intersecting link segments with common attributes between two terminating nodes Links have no connection with other links except at the start or end via common shared terminating nodes points All links contain their terminating coordinates Links may form the boundaries of polygons and may be shared between polygons See also line link and node data A form of vector data in which linear features are represented as links Links are terminated where they intersect other links These intersection points and link ends may carry nodes whose feature records express the geometric relationships between links link and node structure A data structure in which links and nodes are stored with cross referencing map The representation on a flat surface of all or part of the earth s surface intended to be communicated for a purpose or purposes transforming relevant geographic data into an end product which is visual digital or tactile map generalisation A reduction in map detail so that the information remains clear and uncluttered when map scale is reduced May also involve resampling to larger spacing and or a reduction in the number of points in a line map header Data at the start of the digital map file describing that data I
65. es The point has been digitised relative to the map feature it describes and the actual point represents one of the standard positions shown in figure 3 5 Figure 3 5 Standard Ordnance Survey text positions Names are normally placed on the printed map parallel to the horizontal grid Position 0 is supplied The text string may start end or be centred on this coordinate pair the relationship of the text to its coordinate pair is expressed as an original digitised position Where the position of text features are recorded one of these positions is digitised Hierarchical position 5 Ol Ordnance 7 a aa patel v3 0 rown copyrig Survey Page 3 19 Meridi ide chapter 3 E45 Ordnance voe 1 3 2000 Gronn dot Survey Page 3 20 6 Hydrology Each water area contains a seed point identifier which carries a feature code and the associated attribute Each link for water boundaries carries a feature code To maintain positional relationship features in this layer may be adjusted and fitted to the hierarchy See the note at the beginning of Feature layer descriptions on page 3 15 Dark links have been used to maintain the connectivity of the network across lakes and reservoirs Where links entering and leaving the lake or reservoir carry the same name the dark link is attributed with this name Hierarchical position 6 Figure 3 6 Dark link diagram showing connectivity A river and tributaries f
66. fied in the Database Header Record DBHREC as supplied in NTF General The following are the record definitions for the transfer of Meridian 2 data in NTF Volume Header Record VOLHDREC Database Header Record DBHREC Feature Classification Record FEATCLASS Attribute Description Record ATTDESC Section Header Record SECHREC section body see Point and line features name detail node detail e Volume Terminator Record VOLTERM Section body This comprises all the features within the tile that correspond to the feature types selected by the customer Point and line features Point feature Each point feature is depicted by the use of the following records Description in NTF POINT RECORD POINTREC GEOMETRY RECORD GEOMETRY 1 ATTRIBUTE RECORD ATTREC Line feature Each line feature is depicted by the use of the following records Description in NTF LINE RECORD LINEREC GEOMETRY RECORD GEOMETRY1 GEOMETRY CONTINUATION RECORDS ATTRIBUTE RECORDS ATTREC Ol Ordnance Meridian user guide chapter 6 survey v3 0 12 2000 Crown copyright Page 6 11 Ordnance Survey Meridian user guide chapter 6 v3 0 12 2000 Crown copyright Page 6 12 Geometry records Geometry records contain the coordinate position s in metres of the feature Point features contain one coordinate pair line features contain 2 or more coordinate pairs Geometry Continuat
67. figure which are not dependent on position such as connectivity and relationships between lines nodes and polygons transfer format The format used to transfer data between computer systems In general usage this can refer not only to the organisation of data but also to the associated information such as attribute codes which are required in order to successfully complete the transfer transfer medium The physical medium on which digital data is transferred from one computer system to another For example CD ROM transfer set A specific NTF term for the data together with its supporting information which the customer receives update The process of adding to and revising existing digital map data to take account of change vector A straight line joining two data points vector data Positional data in the form of coordinates of the ends of line segments points text positions and so on volume A physical unit of the transfer medium that is a single disc i Ordnance yoia user guide appendix A v3 0 12 2000 Crown copyright Survey Page A 13 Meridian user guide appendix A Oo Ordnance v3 0 12 2000 Crown copyright Appendix B Product performance report form Please post or fax a completed copy of this form to Ordnance Survey Meridian 2 Product Manager Room C433 Romsey Road SOUTHAMPTON S016 4GU Fax 023 8079 2001 Please send any data queries suggestions or general comments
68. ht margin 500 ground metres Layer G8050571 The derived scale of the product is dependent upon the source data Lower right margin 500 ground metres Layer G8050571 The representation of a road track or path is no evidence of a right of way The alignment of tunnels is approximate Lower right margin 500 ground metres Layer G8050571 Date of last amendment dd Mmmmmmmmm CCYY Lower right margin 500 ground metres Layer G8050571 Product specification Figure 8 1 Layout of footnotes Ordnance Meridian user guide chapter 8 rv v3 0 12 2000 Crown copyright Su ey Page 8 9 Meridian user guide chapter 8 Oo Ordnance v3 0 12 2000 Crown copyright Chapter 9 DXF file structure for Meridian 2 General The following paragraphs describe the DXF group and section structure for the transfer of Meridian 2 It is assumed that the reader of this chapter is familiar with the AutoCAD release 12 reference manual which is published by Autodesk Ltd Cross Lane GUILDFORD GU1 1UJ web site www autodesk co uk or an equivalent document published by the reader s software supplier if a CAD package other than AutoCAD is to be used Meridian 2 DXF files containing Ordnance Survey data can be very large and so are supplied on CD ROM media only This chapter gives a detailed breakdown of the data structure of Meridian 2 in DXF This is a two stage procedure which consists of 1 Diagramm
69. ier for administrative areas DLUA ID a unique identifier for a developed land use areas Proper name the definitive name for a developed land use area or railway station Rail ID a unique railway link identifier Settlement name text Station ID a unique railway station identifier Admin name an administrative area name Text independent text Forest ID a unique identifier for forest areas Water area a unique identifier for water area Water link a unique identifier for water links Height ID a unique identifier for gridded height Includes London borough and unitary authority area Unique identifiers Unique identifiers are used to uniquely identify some features within Meridian 2 These are Ordnance Survey Roads Database Reference OSODR this uniquely identifies any road link or road node within the national ROADS database and is therefore compatible with the OSCAR family of products Interchange of data between Meridian 2 and OSCAR is possible with software modification Railway and railway station identifiers these uniquely identify any railway link or railway station within the national Meridian 2 database Developed land use area identifier this uniquely identifies any developed land use area seed point within the national Meridian 2 database Global identifier this uniquely identifies any administrative area seed point within the 10 km by 10 km tile Water identifier
70. ight Figure 9 7 Style Table level 3 Key one or more o optional ENDTAB SIYEE GROUP DEFINITIONS Figure 9 8 The Style Table will contain the text file load instructions for SIMPLEX SHX MONOTEXT SHX Figure 9 8 Level 4 Key one or more STYLE DEFINITIONS STANDARD FLAGS GROUP FIXED TEXT HEIGHT GROUP PRIMARY FONT FILE NAME GROUP BIG FONT FILE GROUP LOS Ordnance Survey Meridian user guide chapter 9 v3 0 12 2000 Crown copyright Page 9 15 Ordnance Survey Meridian user guide chapter 9 v3 0 12 2000 Crown copyright Page 9 16 Blocks Figure 9 9 Level 2 Key one or more o optional SECTION START SECTION START o BLOCKS SECTION ENDSEC GROUP Figure 9 10 BLOCKS GROUP Figure 9 10 Level 3 Key one or more BLOCK BLOCK NAME Z GROUP ENTITIES i Ordnance i oe oa iS v3 0 rown copyright Survey Page 9 17 Ordnance Survey Meridian user guide chapter 9 v3 0 12 2000 Crown copyright Page 9 18 Entities Section The Entities Section will contain DXF entities for e Ordnance Survey map footnotes data INSERT entities e Grid and neatline TEXT and LINE entities and Ordnance Survey features TEXT POLYLINE and INSERT entities Extended entity data will be used to store attributes The structure of each different entity is as follows
71. inear features for example a developed land use area boundary is treated as a polyline in layer G8056300 Name features Name features are treated as free standing text data There is no explicit relationship in the data between a text feature and the point or line feature to which it belongs Ordnance Survey distinguishes between layer name types for example place names and station names by placing each name type in a separate DXF layer Ordnance Survey Meridian user guide chapter 8 v3 0 12 2000 Crown copyright Page 8 3 Ordnance Survey Meridian user guide chapter 8 v3 0 12 2000 Crown copyright Page 8 4 Text has position expressed as a single coordinate pair held as X and Y offsets from the map origin south west corner Text which is double or treble banked is treated as two or three separate features The text string may be considered to be contained within an envelope whose bottom left hand corner is positioned on this coordinate pair Text is oriented that is it may run from west to east across the map or it may be plotted at some other angle measured anti clockwise from grid east Drawing content and format Coordinate system The coordinate system is National Grid NG The National Grid coordinates are to a resolution of 0 01 metre This is the resolution of the source data Height No height attributes are applied to any feature See page 3 21 Layer names S
72. information about empty tiles Volume Terminator Record defines the end of the transfer set Note Where Meridian 2 height differs from Meridian 2 full dataset a record example will be shown Record Name VOLHDREC DBHREC FEATCLASS SECHREC ATTREC POINTREC NODEREC GEOMETRY1 LINEREC ATTDESC TEXTREC TEXTPOS TEXTREP COMMENT VOLTERMI Oo Ordnance Survey Meridian user guide chapter 7 v3 0 12 2000 Crown copyright Page 7 1 Oo Ordnance Survey Meridian user guide chapter 7 v3 0 12 2000 Crown copyright Page 7 2 Volume Header Record VOLHDREC 01 Field Position Format Value example REC_DESC 01 02 A2 01 DONOR 03 22 A20 ORDNANCE SURVEY lt 5S gt RECIPIENT 23 42 A20 lt 20S gt TRANDATE 43 50 DATE yyyymmdd SERIAL 51 54 14 0000 VOLNUM 55 56 12 nn NTFLEVEL 57 57 l1 3 NTFVER 58 61 R4 2 0200 NTFOR 62 62 A1 V EOR 63 63 A1 or lt S gt DIVIDER 64 64 A1 CONT_MARK 65 65 l1 0 EOR 66 66 A1 Record example Description Not used Supply date Not used Volume number 01 to 99 NTF Level 3 NTF Version 2 0 Variable length records Sets EOR to on formatted media or default for formatted media Divider used to terminate variable length text fields No further records Record terminator O1LORDNANCE SURVEY 2000090100000130200V 0 12345678901234567890123456789012345678901234567890123456789012345678901234567890 Template Da
73. ion Records are used where required X_COORDS Y_COORDS and QPLAN are treated as separate fields Name detail Each cartographically positioned name is depicted by the use of the following records Description in NTF Records Text details are only given when a name has been cartographically positioned The Attribute Record ATTREC contains the definitive name and is pointed to by the Text Record TEXTREC The Text Record TEXTREC points to the Attribute Record ATTREC and also points to the Text Position Record TEXTPOS The Text Position Record TEXTPOS refers back to the Text Record TEXTREC and points to the Geometry Record GEOMETRY 1 containing the coordinates of the digitised position The Text Position Record TEXTPOS also points to the Text Representation Record TEXTREP which contains the standard digitising position and orientation of the text All other names are held as attributes only Node detail Node feature Each node feature is depicted by the use of the following records Description in NTF NODEREC NODE CONTINUATION RECORD GEOMETRY RECORD GEOMETRY 1 POINT RECORD POINTREC ATTRIBUTE RECORD ATTREC All links in Meridian 2 terminate in explicit node records each node is related to a point and its attributes via a common geometry record This structure allows an attribute with a node within the constraints of NTF Records Node Record NODEREC transfers details of
74. low into a lake The amalgamation of these is a dark link running through the middle of the lake and outputting as a river again 7 Woodlands Each link for woodland boundaries carries a feature code Each woodland area contains a seed point identifier which carries a feature code and the associated attribute To maintain positional relationship features in this layer may be adjusted and fitted to hierarchy Hierarchical position 7 8 Gridded height Height information is produced in the form of a digital terrain model DTM style data Gridded height information is averaged from the 50 m resolution Land Form PANORAMA dataset to a resolution of 200 m and rounded down to the nearest 1 m value i Ordnance Meridian user guide chapter 3 v3 0 12 2000 Crown copyright 1 Survey Page 3 21 Meridian user guide chapter 3 Oo Ordnance v3 0 12 2000 Crown copyright Source of Meridian 2 Chapter 4 Quality statement Meridian 2 data are derived from large scale and small scale digital databases The data capture source and scales are Feature Road network Railways County district and London borough for England Unitary authority areas for Wales Unitary authority areas for Scotland Coastline Developed land use areas and place names Hydrology Woodlands Gridded height Original data source ROADS centre lines OSCAR Route Manager Large scale database Boundary Line Boundary
75. lue example 44 01 Description Unique text position record identifier cross reference from TEXTREC Pointer to TEXTREP record Pointer to GEOMETRY 1 record No further records Record terminator 12345678901234567890123456789012345678901234567890123456789012345678901234567890 Template Text Representation Record TEXTREP 45 Field Position Format Value example Description REC_DESC 01 02 A2 45 TEXR_ID 03 08 16 Unique text representation record identifier cross reference from TEXTPOS FONT 09 12 14 0004 Text font Identity TEXT_HT 13 15 R3 1 Text height in millimetres DIG_POSTN 16 16 l1 Digitising position 0 8 ORIENT 17 20 R4 1 Anticlockwise from grid east CONT_MARK 23 23 l1 0 No further records EOR 24 24 Al Record terminator Record example 450000070004020300000 12345678901234567890123456789012345678901234567890123456789012345678901234567890 Template Oo Ordnance Meridian user guide chapter 7 v3 0 12 2000 Crown copyright Survey Page 7 31 i Ordnance Survey Meridian user guide chapter 7 v3 0 12 2000 Crown copyright Page 7 32 Comment Record COMMENT 90 Field Position Format Value example Description REC_DESC 01 02 A2 90 RECORD_TYPE 03 04 12 Changed NTF record type RECORD_ID 05 17 A13 Unique id OSODR CHANGE_TYPE 18 18 Al DorlorU Type of change CONT_MARK 19 19 l1 0 No further records EOR 20 20 Al Record terminato
76. n a level value of 0 is used a value of 1 used when there is no access from one road to the other at an intersection See figure 3 2 Figure 3 2 Grade separation In this instance the single node will show a level 0 for all links in Node Record 16 as it is possible to access any carriageway from any approach road A bridge over a road that cannot be accessed will show a level value of 1 Proper name PN attribute This attribute defines the road name associated with any link in the ROADS database If a link does not have a proper name then the attribute will not be present Where the road is otherwise not named and part of a named estate the estate name will be allocated to the road i Ordnance Meridian user guide chapter 3 v3 0 12 2000 Crown copyright Survey Page 3 11 Ordnance Survey Meridian user guide chapter 3 v3 0 12 2000 Crown copyright Page 3 12 Parent OSODR PO attribute This attribute identifies the OSODRs of those OSCAR Asset Manager links which have been generalised to form a link or node in Meridian 2 road data This allows the user of the dataset to integrate Meridian 2 road data with the OSCAR Asset Manager dataset by providing pointers back to the original data Roundabout RT attribute This attribute defines whether a node is a generalised representation of a roundabout in the Meridian 2 road data If it is then the node will have a roundabout attribute with
77. nates and distances Units precision for coordinates and distances Units precision for angles Ordnance Survey Meridian user guide chapter 9 v3 0 12 2000 Crown copyright Page 9 5 Meridian user guide chapter 9 Oo Ordnance v3 0 12 2000 Crown copyright Survey Page 9 6 9 SANGBASE Angle zero direction 50 0 0 9 SANGDIR Angle rotation 70 0 1 clockwise angles 0 anti clockwise angles 9 SPDMODE Point display mode 70 9 SPDSIZE Point display size 40 0 0 9 SPLINEGEN Sets the linetype pattern generation around the vertices of a 2 dimensional Polyline 70 1 0 ENDSEC End of Section Tables Figure 9 3 Level 2 Key 0 o optional TABLES SECTION SECTION START ENDSEC GROUP o LINETYPE TABLE Figure 9 4 SECTION GROUP TABLES GROUP The Tables Section will follow the Header Section and will contain three tables e Linetype Table e Layer Table Style Table Ol Ordnance Meridian user guide chapter 9 v3 0 12 2000 Crown copyright d Survey Page 9 7 v3 0 12 2000 Crown copyright oO Ordnance Meridian user guide chapter 9 Survey Page 9 8 Figure 9 4 Linetype Table Level 3 Key 0 one or more LINETYPE o optional TABLE ENDTAB LINETYPE GROUP DEFINITIONS Figure 9 5 The Linetype Table will contain definitions for the following line types e solid
78. nd use area identifier This uniquely identifies any developed land use area seed point within the national Meridian 2 database Global identifier This uniquely identifies any administrative area seed point within the 10 km by 10 km tile Forestry identifier This identifies any forestry area seed point Hydrology identifier This identifies any hydrology area seed point The unique identifiers are unique references and will be maintained except where there has been significant change to a feature The unique identifier may refer to several links representing a linear object across tiles for example a road ora railway which may be chained together across tile edges Thus on adjoining tiles there may be two or more links with the same unique identifier See figure 3 3 Ordnance survey Meridian user guide chapter 3 v3 0 12 2000 Crown copyright Page 3 13 Meridian user guide chapter 3 Oo Ordnance v3 0 12 2000 Crown copyright Survey Page 3 14 Figure 3 3 Unique identifiers Tie id STES Tie id STES O50 DA ObiJS45 P34 BAR Tie id STE Unique identifiers have been assigned to all existing roads links and nodes railway links and railway stations and to seed points for administrative areas developed land use areas hydrology inland water and woodlands Any of these features which are new to Meridian 2 after the initial allocation will be assigned an appropriate unique i
79. nformation about that polygon for example a county name i Ordnance Meridian user guide chapter 2 v3 0 12 2000 Crown copyright Meridian user guide chapter 2 Oo Ordnance v3 0 12 2000 Crown copyright n Survey Page 2 4 Figure 2 2 Polygon 7 8 6 Point A is the polygon seed point for the area attached to this point are attributes such as the feature code which defines the polygon and its definitive name These attributes may be transferred to the polygon itself The polygon in this example comprises nine individual line segments There are also free standing points which are not associated with a defining polygon for example Liverpool Lime Street Station Chapter 3 Meridian 2 explained Features Meridian 2 has two feature classes e Point features e Line features Point features such as administrative area seed points and line features such as roads railways and developed land use areas are arranged into recognisable categories A full listing of individual features is given in chapter 6 Each feature has two components e Feature position Feature attribute data Also explained in this chapter Feature layer descriptions Each feature recorded in Meridian 2 should be considered as a DXF entity Line features are recorded as DXF D x F Line s or Polyline s Point features will be recorded in the data as INSERT BLOCKS Certain standard symbols are defined in
80. on of the terms and conditions of supply and use of Meridian 2 is detailed in the signed Customer contract held by you or your organisation Ordnance Survey makes every effort to ensure that data supplied is free from errors and omissions We will remedy as soon as reasonably practicable errors and omissions that the customer notifies to us in writing It is the customer s responsibility to ensure that data ordered is suitable for the intended purpose We will not be liable to the customer or any other party for any loss damage inconvenience or expense resulting from the use of or reliance upon the data Delivery of Meridian 2 You are advised to copy the supplied data to a back up medium Written notification of any deficiency in the data or damage to the goods must be given to us within 28 days of receipt of your Meridian 2 data Data copyright All Ordnance Survey digital map data are Crown copyright Full details of the conditions under which our digital map data may be processed and or manipulated or copied by a customer whether or not for use on PCs or workstations or for making hard copies are contained in Ordnance Survey leaflet Copyright 1 Business use of our digital and conventional mapping This is available from Copyright Licensing at the address on the previous page You should check the terms and conditions with us before using the data It is also the responsibility of the holder of the digital map data to ensure th
81. ords or 1 or continuation record follows EOR Re A1 Record terminator Note variable integer Record example 14000032FC6411PI043050NMHAMPSHIRE COUNTY 0 1 2 3 4 5 6 7 8 12345678901234567890123456789012345678901234567890123456789012345678901234567890 Template i Ordnance Meridian user guide chapter 7 v3 0 12 2000 Crown copyright Survey Page 7 21 Meridian user guide chapter 7 oO Ordnance v3 0 12 2000 Crown copyright Survey Page 7 22 Attribute Record ATTREC 14 for gridded height point Field Position Format Value example Description REC_DESC 01 02 A2 14 ATT_ID 03 08 16 Unique attribute record identifier VAL_TYPE 09 10 A2 FC VALUE 11 14 14 Feature code VAL_TYPE 15 16 A2 HT VALUE 17 24 18 Height attribute CONT_MARK 25 25 11 0 No further records or i or continuation record follows EOR 26 26 Al Record terminator Note variable integer Record example 14000090FC6762HT000000070 1 2 3 4 5 6 7 8 12345678901234567890123456789012345678901234567890123456789012345678901234567890 Template Point Feature Record POINTREC 15 Field Position Format Value example Description REC_DESC 01 02 A2 15 POINT_ID 03 08 16 Unique point record identifier GEOM_ID 09 14 16 Pointer to GEOMETRY1 record NUM_ATT 15 16 12 01 ATT_ID 17 22 16 Pointer to ATTREC record CONT_ MARK 23 23 l1 0 No further records EOR 24 24 Al Record terminator Record example 150000270
82. p feature will now display the allied attributes of that feature in a dialogue box To interrogate other features the Re Select option on the user dialogue box should be chosen The Cancel option will return the user to a normal AutoCAD session If the eedd command is repeated at the command prompt the facility will again be available to the user The visibility of extended entity data to software other than AutoCAD Release 12 will be constrained by the functionality of those individual software applications These differences in the data are inferred during translation from Ordnance Survey s internal data format to the required customer transfer format Ol Ordnance Meridian user guide chapter 3 v3 0 12 2000 Crown copyright Ordnance Survey Meridian user guide chapter 3 v3 0 12 2000 Crown copyright Page 3 8 Names as attributes The criteria for names attribute attachment are e Admin name NM is an attribute of a seed point in its administrative area for example Hampshire County e Proper name PN is an attribute of a seed point in a developed land use area for example Bexhill or a node point for a railway station for example Great Ayton Station e Text TX is a text string transferred in an attribute record to be displayed as stand alone cartographic text for example Southampton a place name Hydrology WA is an attribute of a seed point in a water area Woodlands FA
83. r Record example 902301J945LPCABAXUO 12345678901234567890123456789012345678901234567890123456789012345678901234567890 Template Field Position Format Value example Description REC_DESC 01 02 A2 90 FREE_TEXT 03 A NO OSCAR DATA FOR THIS TILE CONT_MARK 11 0 No further records EOR ae Al Record terminator variable integer Record example 90NO OSCAR DATA FOR THIS TILEO 12345678901234567890123456789012345678901234567890123456789012345678901234567890 Template Volume Terminator Record VOLTERM 99 Field Position Format Value example Description _DESC 01 02 A2 99 FREE_TEXT 03 A See note below CONT_VOL 4 1 1 l1 0 No continuation volume or i or continuation volume follows EOR 2 2 Al Record terminator Notes If there are further volume s to follow then the FREE_TEXT field comprises the following message End Of Volume nn Transfer Set Continues On Volume nn 1 If there are no further volumes then the FREE_TEXT field will read End Of Transfer Set variable integer Record examples 99End Of Volume 01 Transfer Set Continues On Volume 021 12345678901234567890123456789012345678901234567890123456789012345678901234567890 Template 99End Of Transfer Set0 12345678901234567890123456789012345678901234567890123456789012345678901234567890 Template i Ordnance Meridian user guide chapter 7 v3 0 12 2000 Crown copyright 1 Survey Page 7
84. r 12 not 9 9 Ordnance Survey Meridian user guide chapter 9 v3 0 12 2000 Crown copyright Page 9 3 Meridian user guide chapter 9 Oo Ordnance v3 0 12 2000 Crown copyright Survey Page 9 4 SEXTMIN X and Y drawing extents lower left corner 10 nnnnnnn nn Minimum eastings National Grid coordinates 20 nnnnnnn nn Minimum northings National Grid coordinates 9 SEXTMAX X and Y drawing extents upper right corner 10 nnnnnnn nn Maximum eastings National Grid coordinates 20 nnnnnnn nn Maximum northings National Grid coordinates 9 SLIMMIN X and Y drawing limits lower left corner 10 nnnnnn n X drawing limit lower left corner in the AutoCAD World Coordinate System WCS 20 nnnnnn n Y drawing limit lower left corner in WCS 9 SLIMMAX X and Y drawing limits upper right corner 10 nnnnnn n X drawing limit upper right corner in WCS 20 nnnnnn n Y drawing limit upper right corner in WCS 9 SLTSCALE Global linetype scale 40 100 0 9 SATTMODE Attribute visibility 70 1 This sets attributes to on when the file is open 9 SFILLMODE 70 1 9 STEXTSIZE 40 1 0 9 STEXTSTYLE 7 STANDARD 9 SCELTYPE 6 BYLAYER 9 SCECOLOR 62 256 9 SLUNITS 70 2 9 SLUPREC 70 1 9 SAUPREC 70 Fillmode on if non zero Default text height Current text style name Entity linetype name Entity colour name Indicates colour ID BY LAYER Units format for coordi
85. r of the record in NTF to indicate whether more data is to be found in a continuation record continuation record A specific NTF term A continuation record is used where space does not allow one logical record to be contained wholly within one physical record coordinate pair A coordinate pair is an easting and a northing coordinates Pairs of numbers expressing horizontal distances along original axis Alternatively triplets of numbers measuring horizontal and vertical distances Row and column numbers of pixels from raw imagery are not considered coordinates for the purpose of the standard copyright Copyright is a legal property right which enables the creator of an original work to protect it from unauthorised use Through the Copyright Designs and Patents Act 1988 Crown copyright continues to subsist in all Ordnance Survey products until the end of the period of 50 years from the end of the year in which they were published and in the case of data from the end of the year in which it was extracted from the Ordnance Survey database Crown copyright is vested in The Controller of Her Majesty s Stationery Office who has delegated powers to the Director General Ordnance Survey for the administration of copyright in publications and data including the determination of terms and conditions under which permission for their reproduction is given currency An expression of the up to dateness of data data A representation of facts
86. spond with Nomenclature des Unites Territoriales Statistique NUTS Level 1 Areas e 10km by 10 km tiles Meridian 2 supply formats Meridian 2 is available in e NTF BS 7567 v2 0 Level 3 or e DXF conforming to AutoCAD release 12 with extended entity data Meridian 2 supply media NTF is supplied on CD ROM only DXF is supplied on CD ROM only 5 Ordnance Meridian user guide chapter 1 e v3 0 12 2000 Crown copyright Meridian user guide chapter 2 Oo Ordnance v3 0 12 2000 Crown copyright Survey Page 1 6 Chapter 2 Overview of Meridian 2 Data overview Basic principles Links represent roads railways administrative areas coastline developed land use area Inland water and woodland area lines Nodes represent all intersections of links within each layer changes in attributes in links and link ends Each feature has associated geometry this may be a single coordinate pair for a single point feature for a railway station or two or more coordinate pairs for a linear feature Each feature is classified by means of a feature code Roads railways railway stations administrative area seed points developed land use area seed points inland water and woodland area seed points have unique identifiers ol Ordnance Survey Meridian user guide chapter 2 v3 0 12 2000 Crown copyright Page 2 1 Meridian user guide chapter 2 oO Ordnance v3 0 12 2000 Crown cop
87. t devised by Autodesk by which digital drawings may be transferred between users of CAD computer aided design systems DXF has become an industry standard data format and is used for the transfer of some Ordnance Survey data products eastings See rectangular coordinates edge match The process of ensuring that data along the adjacent edges of map sheets or some other unit of storage matches in both positional and attributes terms entity Something about which data is stored in a databank or database For example building or tree The data may consist of relationships attributes positional and shape information and so on Often synonymous with feature Extended Binary Coded Decimal Interchange Code EBDCDIC An eight bit character encoding scheme Extent of the realm EOR The external bounding lines of Land Line data is EOR The Territorial Waters Jurisdiction Act 1878 and the Territorial Waters Order in Council 1964 confirm that EOR of Great Britain as used by Ordnance Survey is properly shown to the limit of mean low water mean low water springs in Scotland for the time being except where extended by Parliament Ordnance Survey Meridian user guide appendix A v3 0 12 2000 Crown copyright Page A 5 Meridian user guide appendix A oO Ordnance v3 0 12 2000 Crown copyright Survey Page A 6 feature An item of detail within a map which can be either a point or symbol a line or text
88. t may contain information on the source and history of the geometric data within the map and the coordinate system in use as well as holding information essential to the management of Ordnance Survey s digital mapping system map scale The ratio between the extent of a feature on the map and its extent on the ground normally expressed as a representative fraction for example 1 1250 or 1 50 000 megabyte Mb 1 048 576 bytes a measure of data storage capacity name or text feature The proper name or label of an object real world or feature object abstraction consisting of one or more text strings A name position is defined by a coordinate pair National Grid A unique referencing system which can be applied to all Ordnance Survey maps of Great Britain GB at all scales It is based on 100 km squares covering the whole of GB based on a Transverse Mercator Projection It is used by Ordnance Survey on all post war mapping to provide an unambiguous spatial reference in GB for any place or entity whatever the map scale National Transfer Format NTF A format designed in 1988 specifically for the transfer of spatial information it is published as British Standard BS 7567 and is administered by the British Standards Institution It is now the standard transfer format for Ordnance Survey digital map data node An object representation of a point which either does not form any part of a link isolated node or polygon seed point or is
89. tabase Header Record DBHREC 02 Record 1 Field Position Format REC_DESC 01 02 A2 DBNAME 03 22 A20 DDNAME 23 42 A20 DDATE 43 50 DATE DDBASE 51 70 A20 DDBDATE 71 78 DATE CONT_MARK 79 79 11 EOR 80 80 A1 Record 2 Field Position Format REC_DESC 01 02 A2 FCNAME 03 22 A20 FCDATE 23 30 DATE DQNAME 31 50 A20 DQDATE 51 58 DATE DATA_MODEL 59 60 12 CONT_MARK 61 61 11 EOR 62 62 A1 Value example 02 Meridian_02 00 lt 6S gt DEFAULT_02 00 lt 7S gt 19920515 lt 20S gt 00000000 1 Value example 00 Meridian_02 00 lt 6S gt 20000901 lt 20S gt 00000000 00 0 Description Record type identifier Database name Standard data dictionary name Release date of NTF version being used Not used Not used Continuation record follows Record terminator Description Data specification product version Date of data specification Not used Not used No further records Record terminator Oo Ordnance Survey Meridian user guide chapter 7 v3 0 12 2000 Crown copyright Page 7 3 Oo Ordnance Survey Meridian user guide chapter 7 v3 0 12 2000 Crown copyright Page 7 4 Record example 02Meridian02 00 DEFAULT 02 00 19920515 000000001 O0Meridian 02 00 20000901 00000000000 12345678901234567890123456789012345678901234567890123456789012345678901234567890 Template Gridded height record example O2Meridian2 ht 01 99 DEFAULT 02 00 19920515 00000000
90. tained Applications of Meridian 2 There are many potential applications for Meridian 2 These include Environmental analysis flood areas analysis Land management Commercial and or business site development Routing analysis Retail and or wholesale trades Distribution networks e store and or warehouse locations and strategic business expansion and or development e Marketing and media planning e sales force locations and or territories sales prospecting market analysis of customers competitors or outlet densities market analysis of direct mail responses poster distribution TV and or radio advertising regions and product and or brand promotion campaigns Financial Insurance customer bases and e high low risk areas Health e community health and health black spots Leisure activities large site planning for example golf courses tourism and theme park locations Ordnance Survey Meridian user guide chapter 1 v3 0 12 2000 Crown copyright Page 1 3 Meridian user guide chapter 2 oO Ordnance v3 0 12 2000 Crown copyright Survey Page 1 4 What you need to use Meridian 2 Computer hardware Providing that sufficient memory and storage facilities are available there are no constraints on hardware platforms which can be used The range of hardware which can typically be used varies from higher specification personal computers PCs
91. the bearings and number of lines that meet at a point or node The Node Record NODEREC contains references to each Line Record LINEREC that meets at that node and to the Geometry Record GEOMETRY 1 The Geometry Record GEOMETRY 1 is referenced by the Point Records POINTREC containing the feature attributes of the node Where lines do not meet at a previously specified point feature a special point feature is created The Node Record NODEREC can contain details of up to five line features that meet at a node Further lines meeting at that node are written to the Node Continuation Record It is important to note that although the Node Record contains references to its appropriate point and line features the point and line features do not contain references to the node Ordnance Survey Meridian user guide chapter 6 v3 0 12 2000 Crown copyright Page 6 13 Meridian user guide chapter 6 oO Ordnance v3 0 12 2000 Crown copyright Feature information relevant to NTF Point features Point features can exist independently and at the junction or ends of lines The point feature gives a position and attribute to the corresponding node Line features All line features with the exception of where railways cross at different levels are broken when they intersect one another within a layer Note a layer is a subset of digital map data selected on a basis other than position For example one lay
92. the representation of a point at the start or end of a link terminating node The position of a node is defined by a single coordinate pair which is repeated within all links logically connected at that node and or containing it A node is only deleted if the link containing it as a terminating node is deleted northings See rectangular coordinates orientation Orientation of a point or a text feature is measured in degrees anticlockwise from grid east origin The zero point in a system of rectangular coordinates packing Spaces used as fillers to complete a record or field pecked line A line drawn as a series of dashes Ordnance Survey Meridian user guide appendix A v3 0 12 2000 Crown copyright Page A 9 Meridian user guide appendix A oO Ordnance v3 0 12 2000 Crown copyright physical record A physical record may be fixed length containing 80 characters or variable length containing up to 80 characters point A zero dimensional spatial abstraction of an object represented as a coordinate pair point and line data A form of vector data designed for map production in which all map features are designated as points lines or text Point and line data does not carry the topological relationships between features point feature A zero dimensional spatial abstraction of an object with its position defined by a coordinate tuple Points are represented by nodes which may be isolated or part
93. tion Interchange ASCII A seven bit code for encoding a standard character set area A spatial extent defined by circumscribing lines that form a closed perimeter that does not intersect itself area seed A point within an area that can be used to carry the attributes of the whole area for example ownership address and use type attribute An attribute is a property of an entity usually used to refer to a non spatial qualification of a spatially referenced entity For example a descriptive code indicating what an entity represents or how it should be portrayed attribute class A specific group of attributes for example those describing measure serviceability structure or composition attribute code An alphanumeric identifier for an attribute type attribute value A specific quality or quantity assigned to an attribute Ordnance Survey Meridian user guide appendix A v3 0 12 2000 Crown copyright Page A 1 Meridian user guide appendix A oO Ordnance v3 0 12 2000 Crown copyright Survey Page A 2 basic scale The scale at which the survey is maintained For Ordnance Survey mapping three scales 1 1250 1 2500 and 1 10 000 are used Any area is only maintained at one basic scale block Data on magnetic media may be recorded in blocks of characters for more efficient movement within or between computer systems The length of the block will vary according to the medium and the data transf
94. urvey Meridian user guide chapter 9 v3 0 12 2000 Crown copyright Page 9 19 Meridian user guide chapter 9 Oo Ordnance v3 0 12 2000 Crown copyright d Survey Page 9 20 f EXTENDED entities these consist of e Application name 1001 e Control string 1002 e String 1000 one or more e Control string 1002 Figure 9 11 Level 2 Key o one or more ENTITIES o optional SECTION SECTION ENDSEC START ENTITIES GROUP SECTION ENTITIES GROUP GROUP ee ENTITIES Figure 9 12 Level 3 Key one or more o optional o START Z GROUP LINE ENTITY START X GROUP START Y GROUP EXTENDED ENTITIES ol Ordnance 4 Survey Meridian user guide chapter 9 v3 0 12 2000 Crown copyright Page 9 21 oO Ordnance d Survey Meridian user guide chapter 9 v3 0 12 2000 Crown copyright Page 9 22 Figure 9 13 Level 3 Key one or more o optional INSERT GROUP X SCALE FACTOR GROUP INSERT ENTITY Y SCALE Z SCALE FACTOR FACTOR GROUP GROUP ROTATION i ANGLE EXTENDED GROUP ENTITIES Figure 9 14 Level 3 Key one or more TEXT o optional ENTITY ROTATION RELATIVE OBLIQUE X SCALE ANGLE FACTOR ANGLE GROUP GROUP GROUP o o TEXT TEXT HORIZONTAL VERTICAL STYLE NAME GENERATION JUSTIFICATION JUSTIFICATION GROUP FLAGS TYPE TYPE ALIGN ALIGN ALIGN X GROUP Y GROUP Z GROUP
95. using GIS geographic information systems or CAD computer aided design to mainframe computers with specialised translators and applications Computer software Meridian 2 is supplied as inert data and does not include software for data manipulation To exploit fully the potential of Meridian 2 it is necessary to use appropriate application software such as GIS or CAD NTF format allows users of GIS to customise their own definition of the data and or plotting for their specific applications The parameters defining colours line styles text styles symbols and so on should be built into user software Symbol definitions used by Ordnance Survey are given in chapter 3 Meridian 2 may be customised by viewing or plotting features in different colours line styles and scales to suit different applications Certain classes of features may be omitted from customised plans on the basis of selection by feature code DXF transfer format is designed for use with Autodesk Ltd CAD software particularly AutoCAD The parameters defining colours line styles text styles symbols and so on are embedded within the DXF file as is customary with this CAD format Please check with your supplier if you are unsure of your CAD system s compatibility with Meridian 2 Supply Meridian 2 supply options The options for data supply are as follows Complete national cover of Great Britain 2857 tiles e England e Scotland e Wales These areas corre
96. using the space below Quotation or order reference YOUR NAME 0 eee ey oneal AE Company rt mener Wedded nee Address sn rest nine leds LOS Meridian user guide appendix B v3 0 12 2000 Crown copyright Page B 1 Meridian user guide appendix B Oo Ordnance v3 0 12 2000 Crown copyright Survey Page B 2
97. ve to an arbitrary origin on a plane surface for example a map projection a digitising table or a VDU screen resolution A measure of the ability to detect quantities High resolution implies a high degree of discrimination but has no implication as to accuracy For example in a collection of data in which the coordinates are rounded to the nearest metre resolution will be 1 m but the accuracy may be 5 m or worse section In NTF terminology a subdivision of a database In Ordnance Survey terms this equates to a single map sheet that is a digital map file or a tile seed A seed is a digitised point within an area usually a defined polygon for example a lake or woodland but not always for example a geographical seed such as the South Downs seed point A coordinated point an isolated node within an area usually a defined polygon to which alphanumeric information may be attached as an attribute for example a name or a feature code Also known as a polygon seed area seed or representative point segment A chord defined by two consecutive coordinates in a line string source scale The scale of the source information from which the map was digitised that is the scale of survey for a basic scale map or the scale of the source map for a derived map spatial data Data which includes a reference to a two or three dimensional position in space as one of its attributes It is used as a synonym for geometric data Ordn
98. ware Supply Meridian 2 supply options Meridian 2 supply formats Meridian 2 supply media Overview of Meridian Data overview Basic principles Meridian 2 vector data structure ee en oe ak annagarR ADD D D D D D Ordnance Survey Meridian user guide contents v3 0 12 2000 Crown copyright Contents page 1 Oo Ordnance d Survey Meridian user guide contents v3 0 12 2000 Crown copyright Contents page 2 Chapter 3 Meridian explained Features Points and lines Feature position Feature attribute data Feature codes Names as attributes Road number RN attribute Trunk road TR attribute Line length LL attribute Number of parents NP attribute OSODR attribute Link level at node Proper name PN attribute Parent OSODR PO attribute Roundabout RT attribute Junction name JN attribute Settlement name SN attribute Unique identifiers Feature layer descriptions 1 Roads 2 Railways 3 Administrative areas and coastline 4 Developed land use areas 5 Cartographic names 6 Hydrology 7 Woodlands 8 Gridded height 3 1 3 1 3 2 3 5 3 6 3 6 3 8 3 8 3 8 3 8 3 9 3 9 3 11 3 11 3 12 3 12 3 12 3 12 3 13 3 15 3 15 3 15 3 16 3 17 3 18 3 20 3 21 3 21 Chapter 4 Quality statement 4 1 Source of Meridian 2 4 1 Currency 4 2 Accuracy and resolution 4 2 Completeness 4 3 Meridian general specifications 4 3 Chapter 5 The National Grid 5 1 Chapter 6 NTF e
99. xplained 6 1 An overview of Meridian 2 in NTF 6 1 Jackson structure 6 3 Transfer set structure 6 6 Supply of data on formatted media 6 7 Version management 6 10 General 6 10 Section body 6 11 Point and line features 6 11 Name detail 6 12 Node detail 6 13 Feature information relevant to NTF 6 14 Point features 6 14 Line features 6 14 Coordinates 6 14 Bearings 6 15 Attribute codes 6 15 Unique identifiers 6 17 Record IDs 6 17 Feature layers 6 19 Ol Ordnance Meridian user guide contents v3 0 12 2000 Crown copyright survey Contents page 3 Meridian user guide contents oO Ordnance v3 0 12 2000 Crown copyright Survey Contents page 4 Chapter 7 Record structures for the transfer of Meridian 2 in NTF 7 1 NTF Record List Tad Volume Header Record VOLHDREC 01 7 2 Database Header Record DBHREC 02 7 3 Feature Classification Record FEATCLASS 05 5 Section Header Record SECHREC 07 7 6 Attribute Record ATTREC 14 for road links 7 8 Attribute Record ATTREC 14 for road nodes 7 10 Attribute Record ATTREC 14 for administrative area links county district coastline and neat line 7 12 Attribute Record ATTREC 14 for administrative area points and or seeds 7 13 Attribute Record ATTREC 14 for nodes administrative areas developed land use area coastline and railway 7 14 hydrology and woodlands and or edge nodes all layers Attribute Record ATTREC 14 for developed land use area links 7
100. yright Survey Page 2 2 Meridian 2 vector data structure Meridian 2 data within each layer is supplied as vector data in a link and node structure Geographical features are represented as data entities either as points or lines Points are fixed positionally by one coordinate pair for example a railway station Lines are fixed positionally by a series of connected coordinate points to represent linear map features such as roads railways and so on Points and lines within the data model determine the geometric positional characteristics of the data Points and lines within the data model also have associated attributes These give the point and line entities meaning that is they represent the descriptive characteristic of an entity such as a feature code a name or numerical value Lines are also added as closing links neat lines along tile edges these are required to complete the enclosure of an area The closing link has a different feature code to the other links enclosing the area Throughout Meridian 2 no line feature crosses from one tile to the next but a point feature created at the tile edge has the same coordinate value as its partner on the adjacent tile All features having the same feature code are recorded on the same layer DXF has a limited link and node structure within this structure a feature may be a name point or line Each feature is freestanding that is its topological relationship to any other feature

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