GeoNames is switching from the original SRTM data provided by NASA to the processed srtm v4.1 data provided by cgiar. The extract files now contain srtm data where available and gtopo30 elsewhere.

SRTM is digital elevation model from 56° S to 60° N in a three arcsecond (90 m) resolution. The original data provided by NASA contains small holes of no data over water bodies, mountainous regions and desertic regions. Andy Jarvis and Edward Guevara of the CIAT Agroecosystems Resilience project (CGIAR), Hannes Isaak Reuter (JRC-IES-LMNH) and Andy Nelson (JRC-IES-GEM) have further processed the original DEMs to fill in these no-data voids. This involved the production of vector contours and points, and the re-interpolation of these derived contours back into a raster DEM.  The Consultative Group on International Agricultural Research (CGIAR) is a global partnership that unites organizations engaged in research for sustainable development to reduce poverty and hunger, improve human health and nutrition, and enhance ecosystem resilience.

GeoNames has been kindly granted permission to use the processed srtm data. In exchange CGIAR has been given complimentary access to the premium web services. Thanks to Andy Jarvis and all the others involved.

srtm3 elevation for N46 E8 in the Swiss Alps - void areas in red

srtm3 v4.1 N46 E8 in the Swiss Alps - no data voids filled by cgiar

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