Leonard, It's highly unlikely that a Terrapage model would be in an orthographic or stereographic projection. I'm pretty sure Terrex can only support localized projections like UTM and state plane.
If you are trying to guess what CS the terrain is in, take a lat/long you know is on the terrain and figure out which UTM zone it's in. That's the first thing I would try. Also, if you have a projInfo.txt file, that might lend a clue. Glenn Waldron : Pelican Mapping : http://pelicanmapping.com : +1.703.652.4791 On Tue, Dec 16, 2008 at 9:08 AM, Smith, Leonard C <leonard.c.sm...@ngc.com>wrote: > Hello All; > > I have been attempting over the last few months to invert the LVCS > projection in a Terrex Terrapage archive (.txp) file to retrieve an accurate > latitude, longitude, and altitude given the X, Y, and Z coordinates in the > file. > > I have tried the proj4 library, with a stereographic projection, and an > orthographic projection, to no avail. I have had some success with smaller > areas, for instance 2 degrees in latitude and 2 degrees in longitude, but > with larger areas, the pj_inv function fails to give me accurate results. > > Does anyone have any information as to just what projection parameters the > LVCS projection is, such as "+proj=stere +R=", or the like? > > For an example, if I have a latitude of 31 North and a longitude of 49 > East, I have tried the following two projections, and both fail to give me > accurate results: > > "+proj=ortho +lat_0=31N +lon_0=49E" > "+proj=stere +lat_0=31N +lon_0=49E" > > Thanks for any help, > Leonard Smith > > _______________________________________________ > osg-users mailing list > osg-users@lists.openscenegraph.org > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > >
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