Nick, Shayne, I have not looked at VPB in a while, but I believe it expects height values to be referenced to the WGS84 ellipsoid. If that's the case you'll need to convert it first to HAE.
By the way: DTED heights are referenced to the EGM96 geoid (not to the WGS84 ellipsoid). So they need conversion in order to be properly displayed. GDAL (up until recently?) does not convey this information so there's no way for the application to know. You just have to know :) Glenn Waldron / @glennwaldron On Thu, Sep 12, 2013 at 1:45 PM, Tueller, Shayne R Civ USAF AFMC 519 SMXS/MXDEC <[email protected]> wrote: > Nick, > > Osgdem will work with the input elevation. It will build the database based > on the input source. For example if you're using DTED and the geocentric > option, it will place the point at the specified elevation (in meters) > above > the ellipsoid. The point is represented in the Cartesian ECEF geocentric > space (e.g. x,y,z). > > The default ellipsoid used is WGS84. You can specify the polar and > equatorial radii in osgdem to fit to another ellipsoid. Just make sure you > specify those radii in your EllipsoidModel class on the rendering side so > that things match up. The EllipsoidModel class also defaults to WGS84... > > HTH > > -Shayne > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Nick > Modly > Sent: Sunday, August 25, 2013 11:46 PM > To: [email protected] > Subject: [osg-users] [vpb] osgdem and HAE/MSL > > Hi, > > When providing elevation data to osgdem. is it expected to be in HAE > (height > above ellipoid), or MSL (mean sea level), or can it tell from the input? > For > example, I am providing elevation data in the AIG/Arc/Info Binary Grid > format (.adf). The data represents the elevation of the area in meters MSL. > However, when I osgpick a point and convert it to Lat-Lon-Alt MSL, the > altitude is off by about 30m (the difference between HAE and MSL at this > location). > > This are the options I ran osgdem with > $ osgdem --geocentric -o output.ive -l 8 -d ./path-to-dted/ -t image.tif > > Is it possible to specify a vertical datum or coordinate system, such as > EGM96? > > > Thank you! > > Cheers, > Nick > > ------------------ > Read this topic online here: > http://forum.openscenegraph.org/viewtopic.php?p=55984#55984 > > > > > > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > >
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