Software Help with Software Geodetic Utilities Plate Motion Calculator Geoid Height Calculator
Geoid Height Calculator


The Geoid Height Calculator calculates a geoid undulation at a point whose latitude and longitude is specified. The program is designed to use the potential coefficient model EGM96 and a set of spherical harmonic coefficients of a correction term.

The correction term is composed of several different components, the primary one being the conversion of a height anomaly to a geoid undulation. The principles of this procedure were initially described in the paper: Use of Potential Coefficient Models for Geoid Undulation Determination Using a Spherical Harmonic Representation of the Height Anomaly/Geoid Undulation Difference by R.H. Rapp, Journal of Geodesy, 1996.

This program is designed to be used with the constants of EGM96 and those of the WGS84(G873) System. The undulation will refer to the WGS84 ellipsoid.

Specific details of the undulation computation will be found in the joint project report describing the development of EGM96. This program is a modification of the program described in the following report: A Fortran Program for the Computation of Gravimetric Quantities from High Degree Spherical Harmonic Expansions, Richard H. Rapp, Report 334, Department of Geodetic Science and Surveying, The Ohio State University, Columbus, 1982. This program was put in this form in December 1996. RHRAPP.F477.NONLY


Enter latitude and longitude (in either Decimal Degrees or Degrees Minutes Seconds), and GPS height (ellipsoidal height) and then submit.

NOTE: For multiple point entry, use comma-delimited lists in the entry boxes, but make sure that each entry box used has the same number of comma-delimited entry values.


degrees North (or decimal degrees)
minutes North
seconds North

NOTE: for 56 degrees 15 minutes South, you can enter the latitude as:
a) Decimal Degrees in just the first field, e.g., -56.25
b) Degrees Minutes Seconds in their respective fields, e.g., -56 degrees, 15 minutes.


degrees East (or decimal degrees)
minutes East
seconds East

NOTE: for 102 degrees 30 minutes West, you can enter the longitude as:
a) Decimal Degrees in just the first field, e.g., -102.5
b) Degrees Minutes Seconds in their respective fields, e.g., -102 degrees 30 minutes.

GPS Elevation: meters

Last modified: Thursday, 22-Feb-2018 20:44:37 UTC


Sponsored by

National Science Foundation Logo National Aeronautics and Space Administration Logo