Usage: geopdvc.pl  --rov <vnta|tibr> --dive <dive#>  
		   --olat <lat> --olon <lon>   
		   --elevscale <depthExag> --terrain <area/coverage>
		   --ordinal <number>
		   
Must provide a pair of rov and dive.
Optional, but suggested, is the GDC geoOrigin lat & lon  (olat & olon) values
	
	-olon:        geoOrigin Longitude (must be the same as all 
	              other geoVRML worlds included in the visualization)
	-olat:        geoOrigin Latitude (must be the same as all 
	              other geoVRML worlds included in the visualization)
	(if these options are omitted then the GeoOrigin table in Expd 
	 will be examined for an area that is within 5 degrees of the dive 
	 midpoint.  if one is found then the latitude & longitude of that 
	 GeoOrigin will be used.)
	
	-elevscale:   number to multiply by depth values for vertical 
	              exaggeration (default is 1.0)
	-terrain:     e.g. cencal/MontereyC_bath
	-ordinal:     number of dive in sequence to be displayed (0, 1, 2, ...)
	              To be used for testing as the intended use is to have an 
	              asp set the offset & enabled.