Geosoft mapping software for geophysics, geology, geochemistry
 

How To: Import Lacoste Romberg gravimeter readings into Gravity and Terrain Corrections module

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Problem/Symptom:
Gravity and Terrain Corrections does not support Lacoste Romberg dump files, only Scintrex CG-3, CG-5 and Geosoft RAW file formats.


Environment:
Applies to all versions of Oasis Montaj. For use with the Gravity and Terrain Correction extension.


Resolution:

1. The Geosoft RAW format consists of a simple 3 line header followed by the data in columnar ASCII form. Save the Lacoste dump file in Excel as a TAB delimited file, so that the format is in ASCII columns.

2. Add the 3 line header (lines 2 and 3 essential) using a text editor such as Notepad. Change the file extension to .RAW.

3. It is necessary to have at least one parameter on line 2. Just add the date (dt=yyyy/mm/dd) and add the rest using the processing parameters dialog box off the Gravity Menu.

4. Example of bare minimum required for import as RAW:
**********************************************************************************************
Line 1: Can be your project name, e.g. "Carabelly Gravity Project"
Line 2: dt=1994/06/15
Line 3: Line Stn X Y Date Time Rdng In_Ht Elev
Line 4: 0 1000 * * 1994/06/15 05:18:29 4604.637 * *
Line 5: * * * * * * * * *

and so on
**********************************************************************************************

5. A note on treatment of station numbers:

Where type is specified:
1 - No negative station numbers
Line Stn Type X Y Date Time Rdng In_Ht Elev
0 9062 0 * * 1994/06/15 05:18:29 4604.637 * *
0 5715 1 * * 1994/06/15 05:41:14 4603.782 * *

9062 is imported as a basestation reading.

2 - Negative station numbers
Line Stn Type X Y Date Time Rdng In_Ht Elev
0 9062 0 * * 1994/06/15 05:18:29 4604.637 * *
0 -5715 1 * * 1994/06/15 05:41:14 4603.782 * *

Type column overrides negative values...i.e. Station 9062 imported as basestation, -5715 is imported as a normal station

Where type is not specified:
3 - No negative station numbers - All stations imported as normal readings

4 - Negative numbers - imported as base stations.