I've added code to compute the geoid height and its gradient to
GeographicLib. The code interpolates into a grid of data values and the
EGM84, EGM96, and EGM2008 geoid models are supported. A caching scheme
allows the large grids required by EGM2008 to be supported even on
machines with small memory.
Example: the height of the EGM96 geoid at Timbuktu
echo "16d46'33N" "3d00'34W" | ./GeoidEval
=> 28.7068 -0.02e-6 -1.73e-6
The first number is the height of the geoid (RMS error is 1mm) and the
2nd and 3rd are its slopes in the northerly and easterly direction.
For details see:
http://charles.karney.info/geographic/geoid.html--
Charles Karney <
[hidden email]>
Sarnoff Corporation, Princeton, NJ 08543-5300
Tel: +1 609 734 2312
Fax: +1 609 734 2662
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