In recent years I have used this source https://dds.cr.usgs.gov/srtm/version2_1/SRTM3/ to retrieve elevation data from files in .hgt format. The problem is that these data have holes, so I'm looking for a more recent source of SRTM data, which I found here http://srtm.csi.cgiar.org/srtmdata/ with .tiff format files

The holes have been filled, that's good, but the overall quality of the data returned is really worse, and I do not understand why.

I made an example of traces on contour lines using both sources, and here are the results I get: https://www.visugpx.com/yXT5LMErgk

You can compare the graphs for traces on 500-meter contour lines (on a steep terrain), 320 meters (hilly terrain) and 210 meters (flat terrain), and see that for the SRTM v2 .hgt source I have a margin an error of a few meters, while for the source SRTM VR .tiff there is up to 30 meters difference.

Is this problem known? Are there other sources you would recommend?


1 Answer 1


OK, I found the probleme

The script I used to read .tif files has a error, http://www.osola.org.uk/elevations/index.htm

I'll mail the author

The returned values are better

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