Creating grids (old) (G07a)
Contents
1. 1Cell 2 Cell Smoothing Smooth Iterat E Masking Status Tile Samples Save As Final 1 33 raw_grid 0 Tip You can view statistics for the gridding process in the Report window Choose Report from the Window menu to view it 7 Exit from the tool To exit from the Gridding tool choose Quit from the File menu Library Help Top 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Creating grids old G07a 9 Library Help Top lt 4 Back gt For a better view of your grid Examine the You can use the Visualisation Tool to examine your grid Recall the instructions in grid with a The Visualisation tool G05 visualisation tool Key points for this guided tour In this guided tour you have used the Gridding tool to Transform a line dataset to a grid dataset The INTREPID Gridding tool Transforms line and point datasets to grid datasets Supports a range of gridding techniques for different data characteristics Supports the extensive range of grid based processing and enhancement techniques offered by INTREPID Frequently Asked Questions Q How big can my datasets be A The INTREPID Gridding tool supports extremely large grids it is routinely used to produce grids of 100 000 000 grid points The tool offers a tiling system that allows computers of modest size to grid very large datasets Q Can import or export my favourite grid format A INTREPID native grid format2. INTREPID User Manual Creating grids old G07a 8 Library Help Top lt 4 Back gt Tip We recommend that the grid cell size is about 1 5 the acquisition line spacing If you dont know the acquisition line spacing you can measure it using the Windows Visualisation Tool or UNIX Visualisation tool The guided tours introducing these tools each include a line spacing measurement activity See The Visualisation tool G05 The line spacing for the ebagoola_S dataset is approximately 400m Tip Minimum Curvature is a smoothing process which INTREPID repeats according to the number of iterations you specify Each iteration produces a change in some cell values The changes become smaller with each iteration When the maximum change for any cell falls below the Maximum Residual or INTREPID has completed the required number of iterations the Minimum Curvature process stops Consult the reference manual for an explanation of the other parameters Perform the 6 Perform the gridding operation gridding operation Choose Apply INTREPID creates and saves your new grid dataset as specified You can view the gridding process in the Main Gridding window Intrepid Gridding Tool 3 1d File Initial Grid Precision Visuals Windows Help Gridding Parameters Grid Size 80 00 Extrapolate Cell E L Rotate Line Data Laplace Iterat DJ Minimum Curvature Iterations Max Residual 050 Curve Tension amp Honour Original Data
3. Help Top 4 Back gt The INTREPID gridding tool can e Process datasets of unlimited size and e Create multiband grids from several line or point dataset fields Grid datasets form the basis for image based enhancements such as Spectral domain FFT and convolution filtering e Interpretation tools Kuler deconvolution grid based depth methods Image based hard copy products Context of this guided tour The data used in this tour 1s raw and contains noise spikes and corrugations In the context of your data processing cycle the tour represents an early examination of a set of line data before it is refined by other INTREPID tools Location of sample data for Guided Tours We provide two complete sets of sample datasets one in INTREPID format and one in Geosoft format INTREPID works equally well with both formats When you want to open a dataset navigate to the directory containing the required data format Where install_pathis the path of your INTREPID installation the project directories for the Guided Tours sample data are install_path sample_data guided_tours intrepid_ datasets and install_path sample_data guided_tours geosoft_datasets For example if INTREPID is installed in C Program Files Intrepid Intrepid4 5 nnn then you can find the INTREPID format sample data at C Program Files Intrepid Intrepid4 5 nnn sample_data guided_tours intrepid_ datasets This is the default location for the sample data If
4. purpose suitable for all data types It uses cell centroids The Box Filter method is faster than the Nearest Neighbour method Variable Density This method is designed to minimise grid artifacts for datasets which have a variable data sampling eg land gravity marine gravity and bathymetry data Refinement methods Minimum Curvature This iterative process smooths the grid points after the initial gridding Applies only to interpolated grid values thus the original data points are honoured Library Help Top 2012 Intrepid Geophysics 4 Back gt
5. the Project Manager Navigate to the directory Creating grids old G07a 4 4 Back gt install _path sample_ data guided_tours intrepid datasets Start the Gridding tool See Locating datasets viewing statistics launching tools G02 for instructions about navigating to different directories lolx File Dataset Editors Level Grid Display Print Filtering Radiometrics Gravity Interpretation Utility Betas File name File type amp cil a E Documents and Settii Library Help Top DRIVERS a dircos_grid PD ers Intrepid grid file ibmtools a dircos_grid spectrum asc File icons dircos_grid_R ft File E Intrepid ja dircos_grid_R PD ers Intrepid grid file H 0 algorithm ja dw_grid fit File H E bin ja dw_grid PD ers Intrepid grid file j I classes a dw_grid spectrum ase File H 0 config E3 ebagoola_A DIR Intrepid Database 4 cookbook EJ ebagoola_B DIR Intrepid Database H E dof lat ebagoola_S DIR Intrepid Database 4 examples E3 ebagoola_ST DIR Intrepid Database H 0 filters a euler_s DIR Intrepid Database H font E3 euler_ss DIR Intrepid Database gt H 0 form ia a Field Statistics ia Ai Field Allas Datum Projection Brecis on Default For Exp 9 lut i fid l Fiducial _ Signed32B 6 0 a 9 lyrodata __line LineNumber _ Signed32B 6 0 H 0 manuals linetype __LineType Signed1 6B 8 0 9 proj o raw mag _ o EEE4By
6. you have installed INTREPID normally the data resides there If you have installed INTREPID elsewhere the exercises will work just as well Just use the appropriate pathnames For more information about installing the sample data see Sample datasets installing locating naming in INTREPID Guided Tours Introduction G01 For a more detailed description of INTREPID datasets see Introduction to the INTREPID database G20 For even more detail see INTREPID database file and data structures R05 Should you complete this guided tour W Library Help Top This guided tour is intended for introductory level users and contains full detailed instructions The gridding process it demonstrates is a fundamental INTREPID process You should complete this tour as part of a thorough evaluation of INTREPID In later guided tours you can use the Gridding tool to produce grids from the results of the exercises you complete 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Creating grids old G07a 3 Library Help Top lt 4 Back gt What you will do Flow Chart Summary Process Outputs Line Specify a Z dataset field to grid Configure gridding gt one _ Parameters dataset Library Help Top 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Library Help Top Steps to follow Navigate to the 1 data and start the tool Start
7. INTREPID User Manual Creating grids old G07a 1 Library Help Top 4 Back gt Creating grids old G07a Top Creating a grid from a set of line or point data is a fundamental operation with geophysical data The INTREPID Gridding tool is a powerful instrument for creating grids This guided tour conducts you through a simple gridding operation deriving a grid dataset from a set of line data The following illustration shows stages in a line data gridding process and the final result in the Gridding tool window Intrepid Gridding Tool 3 1d File Initial Grid Precision Visuals Windows Help Gridding Parameters Grid Size 80 00 Extrapolate cel 5H Nominal B earing C Rotate Line Data Laplace Iterat gt Minimum Curvature Iterations Max Residual Curve Tension 0 00 EJ Honour Original Data O1Cell 2Cell J Smoothing Smooth lterat Ll Masking Status Tile Samples Save As Final 1 33 raw_grid 0 Overview The Gridding tool enables you to produce a grid raster dataset from a field of a line or point vector dataset You can use the Gridding tool to produce grids from e Point data eg gravity Line data eg aeromagnetics including both e Regularly spaced data eg aeromagnetics and e Variable density data eg marine gravity Library Help Top 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Creating grids old G07a 2 Library
8. dow menu The Gridding tool has four window views The Main window displays the gridding process and enables you to set parameters The Report window displays a list of all of the settings for the current grid process The Original Data window displays the line or point data in its original form The Tiling Control window enables you to coordinate the process for very large datasets Set parameters for the process Grid Cell Size 80 Extrapolate Cell 5 Nominal Bearing 90 Minimum Curvature On Maximum Residual 05 Smoothing On From the Windows menu choose Main Gridding Intrepid Gridding 3 7 release cut 179 Fie Initial Grid Precision Quality window Help Main Gridding Process Begin ZIN C Intrepid tutorial t Outputimage C Intrepn Original Data LineType C Intrepid t Tiling Control w IM imtronid hikar al Set Grid Cell Size to 80 Extrapolate Cell to 5 and Nominal Bearing to 90 by typing these values in their respective text boxes Select the Minimum Curvature grid refinement option and turn on the Smoothing check box Set Maximum Residual to 05 by typing the value into the corresponding text box Select the 2 Cell Option Select the Std standard Kernel for Minimum Curvature refinement Grid Cell Size 80 00 Extrapolate ceb Nominal Bearing Rotate Line Data Grid Refinement None C No Internal Nulls Minimum Curvature 2012 Intrepid Geophysics 4 Back gt
9. ine dataset directory INTREPID displays the Enter band number dialog box Enter Number of Bands 7 Current Band Number 171 Bands start at 1 Ok Cancel Leave these settings unchanged Click OK Use the Calculate Average Strike facility in the Report window to estimate the bearing of the traverse lines From the Window menu choose Report File Initial arid Precision Quality Window Help w Main Gridding Original Data Tiling Control INTREPID displays the Report window i0 xj PIN C atiepid tAcsials ebageole_S DIRM C a Dutputinage C Intiepet tuteriabs raw _ gid Srm Calceinte Average Striko Type C B Name giridig Comments Audi Stamp v3 7 release cut 179 16 9 2002 Paeamoten logn SaveComveGnds Ko SaveOngn al auestiod No SaveCurvatuetind No 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Creating grids old G07a 7 Library Help Top Set the gridding parameters Library Help Top Gridding P arameters 4 Back gt Choose Calculate Average Strike INTREPID calculates the average bearing of the traverse lines in the dataset and display the results in an Information dialog box x AN Line Bearing 91 0 Note the Line Bearing value that INTREPID has reported 91 East West Choose OK Tip INTREPID application windows often consist of a deck of window views You can select the view you require using the Win
10. is already compatible with ERMapper and ARC INFO raster formats The INTREPID Export tool can output your data in a wide range of formats including ASCII Geosoft ECS Geosolutions GEOPAK NetCDF and AGSO formats Q Does INTREPID support multiband grids A Yes both the INTREPID Gridding tool and other INTREPID grid processing tools support multiband grids Q Can INTREPID deal with holes in the data A Yes Masking is supported Library Help Top 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Creating grids old G07a 10 Library Help Top lt 4 Back gt Q What gridding methods does INTREPID use A The INTREPID Gridding tool has four gridding methods as shown in the table below and additional grid refinement procedures After the gridding process no matter which method you use INTREPID can refine your new grid using LaPlace smoothing and iterative Minimum Curvature Method Purpose Initial Grid methods Nearest Neighbour General purpose suitable for all data types The interpolation process honours original data which makes this method very accurate Nearest Neighbour is slower than other methods Bi Cubic Spline This method is restricted to line datasets It uses cell centroid values The Fast Grid Bi Cubic Spline method is very fast Trend Spline This method uses adaptive directions to follow the geological strike of the region surveyed Box Filter General
11. sets Enter raw_grid1 in the File Name text box This will be the name of your output grid dataset If you want to output a grid in a different format other than Intrepid you must add the correct extension to the grid name 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Creating grids old G07a 6 Library Help Top Check the line direction Library Help Top lt 4 Back gt For example if you want a Geosoft grid you must type raw_grid1 grd in the File Name text box Intrepid Gridding 3 7 release cut 179 Save Dataset Fie Initial Grid Precision Quality Window Help Load z Field For Gridding z Field Preprocess _Jebagoola_4 a8 anomD_orid PD ers _ Jebagoola_B sa anomL_orid PD ers za mlevel_grid PD ers _Jebagoola_5 sa corr_orid PD ers sa pass_orid PD ers l i ebagoola_5T n dircos_grid PD ers raw grid PD ers _Jeuler_s dircos_grid_R PD ers rtep_grid PD ers J euler_ss dw _grid PO ers smooth_orid PD ers Load Grid For Reprocessing Load Polygon Sub Region Specify Output Grid as Load Options Save Options polyA m K_Th_U_orid PO ers smooth _grid_t PO ers id FPD sti P E L mlew grid PD ers aa stitch_a PD ers Quit Cancel E File name ran_oridi Save as type Data grd cdi nc ers ZA Choose OK Tip The grid dataset you are creating must be stored outside the l
12. t directory for the Gridding Tool otherwise the job file will not load into the Tool 2 Specify the raw_mag field from the line dataset ebagoola_S as the input data From the File menu choose Load Z Field for Gridding INTREPID displays the Select Database dialog box Select the file ebhagoola_S DIR and choose Open Intrepid Gridding v3 7 release cut 179 File Initial Grid Precision Quality Window Help Load Z Field for Gridding z Field Preprocess Select Database ebagoola_4 Ca polyA ebagoola_B Ea polyB euler_ss DIR ebagoola_5 ebagoola _A DIF sa polyA DIF ebagoola_ST sa ebagoola_B DIR polyB DIF Load Grid For Reprocessing Load Polygon Sub Region Specify Output Grid as Load Options Save Options Gridding Setup Wizard Quit File name Jebagoola_ DIF Files of type Data DIR gdb jdbc Cancel Open as read only ZA Ok Cancel INTREPID displays the fields of ebagoola_S in the Load Z dialog box Select click the raw_mag field Choose OK Note Do not choose Apply in the Gridding window until step 6 3 Specify raw_gridl in the install_path sample_data guided_tours intrepid_ datasets directory as the output grid dataset From the File menu choose Specify Output Grid as INTREPID displays the Save Dataset dialog box Ensure that the current directory is install _path sample_data guided_tours intrepid data
13. te 72 E smooth_m IEEESByte 16 2 x x TMAMGS54 IEEESByte 16 2 x_trim TMAMG54 IEEESByte 16 2 a RECYCLER y TMAMG54 IEEESByte 16 2 a System Volume Inforr trim TMAMGS54 IEEESByte I WINDOWS x 4 gt Choose Gridding from the Grid Menu File Dataset Editors Level Display Print Filtering CAJ H Documents and Setti H 0 DRIVERS H ibmtoals H icons Grid Stitch GridMerge Grid Operations Mase INTREPID displays the Gridding Main window Intrepid Gridding 3 7 release cut 179 3 Oj x Fie Initial_Grid Precision Quality Window Help Gridding Parameters Grid Cell Size 190 00 Extrapolate cen 5 Nominal Bearing m Rotate Line Data Grid Refinement None C No Internal Nulls C Minimum Curvature Masking Apply Stop Status Save As 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Creating grids old G07a 5 Library Help Top JOB Load the data to be gridded Specify the output grid Library Help Top lt 4 Back gt You can specify the input output and parameters for the Gridding process in this guided tour using the job file ch06_1 job If you want load it into the Gridding tool as described in Section Task specification job file short cuts in INTREPID Guided Tours Introduction G01 then go to Step 6 Ensure that the directory which contains the job file is the curren
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