Lenny, OK, the "selectorId=60000" means that you have a flat, geographic dataset, i.e., x=long, y=lat. The values may be offset (by the origin values in the projinfo), but it is probably that simple.
Glenn Waldron : Pelican Mapping : http://pelicanmapping.com : +1.703.652.4791 On Tue, Dec 16, 2008 at 1:41 PM, Smith, Leonard C <leonard.c.sm...@ngc.com>wrote: > Hi Glenn; > > Thanks for the ideas. I had quite a lengthy support discussion with a > gentleman from Terrex, and he informed me that they were using the proj4 > library in the projection, that it was on the WGS84 ellipsoid, and more, > including that the projection is WGS84 flat earth, and sent me a spreadsheet > with a whole slew of information. The projInfo.txt file looks like this: > > csm=Projected > originlat=25.000000000000000 > originlon=42.000000000000000 > zunits=1.000000000000000 > selectorId=60000 > dcType=NONE > dcSelectorId=0 > txpOffsetX=0.000000 > txpOffsetY=0.000000 > txpOffsetZ=0.000000 > > And here is one of his replies, which didn't nail down the question of > "what is the projection". I got a "looks like the projection is", not a > "the projection is": > > Lenny, > > The answer is Yes to your question: Just to touch base again, it looks like > the projection we are talking about (from > what I can gather looking at the projections) is an orthographic projection > at the origin that the user specifies. Is > that correct? > > Sorry for the delay. > > Jeff > > Again, thanks for your help, > Lenny > > > ------------------------------ > *From:* osg-users-boun...@lists.openscenegraph.org [mailto: > osg-users-boun...@lists.openscenegraph.org] *On Behalf Of *Glenn Waldron > *Sent:* Tuesday, December 16, 2008 1:04 PM > *To:* OpenSceneGraph Users > *Subject:* Re: [osg-users] Looking for some Terrex Terrapage Archive help > > 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 >> >> > > _______________________________________________ > osg-users mailing list > osg-users@lists.openscenegraph.org > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > >
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