Help for GET_ELV

PURPOSE

Reads the ETOPO2 and SRTM datasets to get an elevation.  The ETOPO2 is a
coarse (2 minute) map of the world.  This program uses a version without
bathymetry (ocean depth, etc.) so ocean lon-lats yield 0.

Both data sets read out in MSL or EGM96 (geoid).  The routine then converts
these to the WGS84 spheroid (as a vertical datum).
	   
CALL
     ELVREF lon lat
  WHERE:
     lon           is the longitude
     lat           is the latitude
     
  
OPERATION

see above.

PERFORMANCE

less than a second

Restrictions

We are still straightening out the high latitudes.
------------


Original Programmer: A. L. Zobrist, 22 Sep, 2008
Current Cognizant Programmer: A. L. Zobrist

REVISION
2022-08-10 B. Crocco afids to opensource (untested)

PARAMETERS: