SRTM outside the USA

[Holger 0]

Hi everyone:just to complete the "guidelines" above: If you're not sure whether your area 'suffers' from a consistent offset, a first good step for checking is using MS TMFViewer.exe, with the appropriate hyl******.bgl and stl******.bgl files from the FS2002/scenedb/... folder as an overlay to your raw elevation .bgl file.I remembered this when looking at Gilles Gauthier's documentation for his SRTM Quebec mesh series; wonderful job with the mesh, Gilles!Unfortunately, it doesn't seem to be possible to use TMFViewer directly to measure the offset.----Two more problems with the SRTM data I discovered, both probably related to radar backscatter issues: 1. Some of the steep mountains in the Rockies and southern BC show regular steps/terraces or deep indentations that aren't there in reality.2. Steep canyons seem to scatter the signal very badly so that the signal isn't usable. For example, most of the Grand Canyon and nearby smaller canyons in Utah are 'black holes' (missing data).Cheers, Holger

[Guest sgreenwood]

Hi Cazador,Just for the record, while some default mesh may be created from GTOPO30 data, especially in your area, not all of it is. I've flown in many areas where the GTOPO30 data is much better (relatively speaking :) ).Below are two images from Northern Iran; the first is the default mesh, the second is GTOPO30 data at LOD7. I've done enough testing of mesh at different LOD levels to know that LOD5 vs LOD7 cannot account for the dramatic differences in these images. The full-size versions are available at:www.fs-traveler.com/cgi-bin/iran-test.zipCheers,Steve