Hello all, I start with dted data and use gdal_translate to convert this data to a geotiff. This geotiff has 278x305 pixels. The lat-lon bounding box has right angles in lat-lon space, but due to the mercator projection being used, the geotiff has some no-data areas along the edges.
I then run osgdem using the following command: osgdem --geocentric -d elevation.tif -l 1 -o elevation.osg --POLYGONAL When I view this elevation.osg file in wireframe I see that the primitives that make up the terrain are large if there is a small elevation gradient and small if there is a large elevtion gradient. This makes sense; it's only using as much detail as needed. For my purposes, I want a set of primitives that is in the same grid as the original pixel map. So, I repeat the osgdem command above but add the --no-terrain-simplification flag. When I look at this osg file in wireframe, I see that it has created a 63x63 pixel terrain, with each pixel made up of two triangles. There is also a second primitiveset that is simply a quadstrip that wraps around the edge of my terrain. This is close to what I want, but my questions is this: Why is the osg terrain 63x63 when the source geotiff was 278x305? What process is osgdem using to determine how many of these two-triangle-pixels to put in each direction in the output product? Do I have any control over these parameters without modifying the osgdem src? I've looked at all the osgdem flags and nothing jumped out at me. Thanks so much for any help you can give me. ------------------ Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=43931#43931 _______________________________________________ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
