[osg-users] Anomalies using VirtualPlanetBuilder

[Paul Brewster]

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



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