Hi Paul, That new image helps quite a bit actually. The elevation values for your image are extremely strange. All of the values are negative except for the areas that are in the craters. I'm using OpenEV to inspect the values and it looks like the craters have extremely high positive values and the rest of your image has negative values.
It seems as if the areas in the craters are NoData and are potentially not being specified correctly. I believe that osgTerrain will just use 0 for values that are NoData, which will typically result in small holes in the data that go *down* to 0. Since your actual elevation values are negative, the holes are going *up* to zero, which is why you see the plateaus. It seems to be that this is a problem with your data, not VPB. Hope this helps you track the issue down! Thanks! Jason On Fri, Apr 4, 2008 at 1:50 PM, Paul Brewster <[EMAIL PROTECTED]> wrote: > Thanks Jason, > > I guess the geo info was lost when I rescaled the image. I'll include > another GTiff with the info in it. The NODATA value is -32767, which is the > smallest value possible, of course. I don't know the exact value of the bad > areas, but if you look closely, you can see craters on top of the > "plateaus", so I don't know if it is purely a NODATA problem. > > Thanks for the help. > > Paul > > Jason Beverage wrote: > > > 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]<mailto: > > [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 > > osg-users@lists.openscenegraph.org > > <mailto: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 > > > > > _______________________________________________ > osg-users mailing list > osg-users@lists.openscenegraph.org > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > >
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