Using geoid files

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Geoid Separation File: This option will incorporate the geoid undulation in determining the orthometric elevation of the measurement. The definition of the geoid model as currently adopted by the National Geodetic Survey is the equipotential surface of the Earth's gravity field which best fits, in a least squares sense, global mean sea level. Orthometric elevation measurements are used in survey calculations.  In order to convert ellipsoid heights (He) as measured by GPS into orthometric elevations (Eo), you must provide for a correction between the GPS-measured ellipsoid (reference ellipsoid) and a constant level gravitational surface, the geoid.  This correction is the geoid undulation (Ug).



How to use Geoid Separation Files with DigiTerra Explorer

1. Copy the Geoid Separation File(s) to the following directory:


Default Geoid Directory



Desktop version:

$DOCUMENTS\DigiTerra Explorer\Geoids

Mobile version:



2. Tap on the geoid_button Geoid File button on the Settings panel > GPS tab

3. Tap on the  New  button on the appeared message box to open the Geoid File panel


Geoid file selection message box



Deactivate  - Deactivates the geoid file usage


Cancel  - Closes the geoid file selection message box


4. Select a geoid file


Geoid File selection panel



Successfully loaded geoid file



Supported geoid file formats:


.DAT files

.BIN files

.GSF files

.GGF files

.GEO files

k-tip-iconYou can download several geoid separation files here:

k-tip-iconThe selected geoid separation file can be applied on the Calculate panel in determining the orthometric elevation of the calculated position.