Image Name                   :  ww15mgh
Boundaries                   :  Lat -90N to 90N ; Lon 0E to 360E
Color Scale, Upper (Red)     :  85.4 meters and higher
Color Scale, Lower (Magenta) :-107.0 meters and lower 
Data Max value               :  85.4 meters
Data Min value               :-107.0 meters
Illuminated from the         :  East 


  This is an image generated from 15'x15' geoid undulations covering the
planet Earth.  These undulations represent the NIMA/GSFC WGS-84 EGM96
15' Geoid Height File.  This file is a global grid of undulations
generated from:  (a) the EGM96 spherical harmonic coefficients and
(b) correction terms that convert pseudo-height anomalies on the ellipsoid
to geoid undulations.  This file may be found at:

    http://164.214.2.59/geospatial/products/GandG/wgs-84/geos.html

The undulations in this file refer to the WGS-84(G873) reference ellipsoid.
We are deeply indebted to the NIMA/GSFC EGM96 team for their work on 
EGM96 and this grid of associated geoid undulations.

Some interesting features to note about this image are:

  Even at 15' resolution, some beautiful features of the global geoid are
obvious.  The major trench systems have obvious impacts on the geoid, as
well as the topography/ocean boundaries (whose geoid signals closely
coincide with the shoreline).

  The Hawaiian Island chain may be followed up through its transition into the
Emperor Seamounts and toward the western end of the Aleutian Islands.

  The structure of seamounts with the Marshall Islands, east of the Mariana
Trench, can be seen in the geoid signal in that area.

  Finally, the well-known geoid low near the tip of India, and the geoid high
over New Guinea stand out, with a great deal of finely detailed structures 
mixed in with these broad features.

das/dgm 6/04/97