Hi Paul, I tried to take a look at the sample file you created, but it doesn't have any coordinate system attached to it so can't reproduce the problems you were seeing with that data.
My gut feeling is that it has something to do with the handling of NODATA values in osgTerrain. What are the actual pixel values of the file you are using where the spikes are occurring? Thanks, Jason On Fri, Apr 4, 2008 at 10:29 AM, Paul Brewster <[EMAIL PROTECTED]> wrote: > Hey all, > > I'm using VPB to build some terrains and have found a few anomalies > going on. I have a single 10240x10240 DEM of part of the moon in a > 16-bit unsigned format. I can run gdalinfo and gdal_translate on it > just fine, so I will include a 2.5% version of the DEM so that you can see > what I am talking about. When I run "osgdem -l 1 --TERRAIN -d DEM.pds" > everything works really well, except I get some areas in the terrain > that just don't look right. My nice round craters suddenly jump out > into plateaus in the middle. It appears that somebody put some > monoliths in my moon craters. Does anybody know what is happening here? > These anomalies are consistent throughout the levels, even if I go all > the way down to full resolution. At first I thought these might be from > signed/unsigned problems. But as I look at the data, I'm not convinced > that is true. Anybody have any ideas what is going on? I'll include > some pictures to show what I mean. > > Thanks for your help. > > Paul Brewster > > Oh, and here is the vital information: > OpenSceneGraph: 2.3.5 > VirtualPlanetBuilder: 0.9.6 > GDAL: 1.5.0 > OS: CentOS 4.5 (linux) > > The header to my DEM: > Driver: PDS/NASA Planetary Data System > Files: LDEM20723Sm.LBL > Size is 10240, 10240 > Coordinate System is: > PROJCS["POLAR_STEREOGRAPHIC MOON", > GEOGCS["GCS_MOON", > DATUM["D_MOON", > SPHEROID["MOON_polarRadius",1737400,0]], > PRIMEM["Reference_Meridian",0], > UNIT["degree",0.0174532925199433]], > PROJECTION["Polar_Stereographic"], > PARAMETER["latitude_of_origin",-90], > PARAMETER["central_meridian",0], > PARAMETER["scale_factor",1], > PARAMETER["false_easting",0], > PARAMETER["false_northing",0]] > Origin = (29.614999890327454,-29.614999890327454) > Pixel Size = (59.229999780654907,-59.229999780654907) > Corner Coordinates: > Upper Left ( 29.6149999, -29.6149999) > Lower Left ( 29.615, -606544.813) > Upper Right ( 606544.813, -29.615) > Lower Right ( 606544.813, -606544.813) > Center ( 303287.214, -303287.214) > Band 1 Block=10240x1 Type=Int16, ColorInterp=Undefined > NoData Value=-32768 > Offset: 1740000, Scale:0.6 > > > > > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > >
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