Objective:
I would like to create a new datum for my project.
Resolution:
In order to create a custom datum, the datum.csv and ellipsoid.csv files in user csv folder need to be modified. We recommend that you make backups of these files, before editing, and perform the edits the Excel.
To edit the ellipsoid.csv file:
- In Windows Explorer navigate to C:\Users\{UserName}\Documents\Geosoft\Desktop Applications 9\csv and open the ellipsoid.csv file.
- Ellipsoid column: ellipsoid name. Enter “*” and a name for your new ellipsoid (e.g. *newellipsoid).
- Code, Major_axis, Eccentricity, 1/f and MapInfo columns need to be edit with the correct information of the Ellipsoid you are entering.
- If your new datum has the ellipsoid information already added to this file (e.g Clarke 1858), you do not need to modify the ellipsoid.csv file.
To edit the datum.csv file:
- In Windows Explorer navigate to C:\Users\{UserName}\Documents\Geosoft\Desktop Applications 9\csv and open the datum.csv file.
- Datum column: Enter “*” and a name for your new datum (e.g. *newdatum).
- Code column: leave it blank as you are adding a datum that is not in the EPSG tables..
- Area of use column: enter the area where this datum will be applied between square brackets “[ ]”, so it can be easily identified (e.g. [local]).
- Datum_trf column: datum transform name as it is in the datumtrf.csv file.
- Ellipsoid column: ellipsoid name as it is in the ellipsoid.csv file
- Esri, ESRISHORTS, MapInfo and Geoid columns: leave it blank if you do not have this information.
- Prime_meridian column: prime meridian value.
Notes:
It is important that you do not edit the csv files in C:\Program Files\Geosoft\{program}\csv. Only edit the csv files in the user folder (C:\Users\{UserName}\Documents\Geosoft\Desktop Applications 9\csv)
In earlier versions of our applications the user csv files where located C:\Program Files\Geosoft\{program}\user\csv.
Related Documents:
Why do some coordinate systems carry a local datum transform while others do not?