While you certainly can accomplish this using GDAL, you'll need to first figure out which hgt file to open, then translate the geographic coordinate to the image coordinate to know what pixel value to lookup.
An alternative solution is OSSIM (http://www.ossim.org/). It has a command-line app called ossim-height. You can use it as follows: $ ossim-height 45 10 Opened cell: /srtm1/N45E010.hgt MSL to ellipsoid delta: 39.049 Height above MSL: 37 Height above ellipsoid: 76.049 Geoid value: 39.049 You can setup a configuration file (see: http://trac.osgeo.org/ossim/wiki/ossimElevationSetup) that points to your directory of hgt files and OSSIM will figure out which file is needed for your query. If you're needing to embed this in an application of yours, you can use the OSSIM API to accomplish the same thing. Check out the source for ossim-height for an example of how to do this. --Matt On Fri, Jun 11, 2010 at 9:33 AM, Gianni Olivieri <gianni.olivi...@gmail.com>wrote: > Hallo, > > I need to extract the altitude of a GPS coordinate from a serie of > HGT (SRTM or DEM) (I've download the entire Eurasia... > > So, for example, If I have a directory with all htg file and I'd like > to know the altitude of this coords: > > 48°01'35.89" N > 8°23'51,86" E > > how can I preceed? > > The elevation in that point is: 761m (google earth result) > I'd like to have a similar results. > > Best regards > > > > -- > Gianni Olivieri > gianni.olivi...@gmail.com > _______________________________________________ > gdal-dev mailing list > gdal-dev@lists.osgeo.org > http://lists.osgeo.org/mailman/listinfo/gdal-dev >
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