[Award Winner] Managing SRTM information with GDAL

[vehrka]

The information from NASA's Shuttle Radar Topography Mission (SRTM) can be used as a basis for hillsades or elevations in fantasy maps. In this tutorial we're going to see how to manage this data using OSGeo Foundation GDAL library. We're going to use this library from the command line utilities included in FWTools.

The idea is to convert the image Figure 1 into the image Figure 2. Well not exactly the image Figure 2, but at least how to obtain the base information:


Figure 1

Figure 2

1.- Getting the data.

You can get NASA's SRTM data from several sources:

• NASA's FTP.
• USGS webpage.
• a Google Earth layer from Mark Mulligan and the London's King's College.

Each source has it's pros and cons. If you are using the NASA's FTP you must first know the coordinates of the zone you want to use and what you get are tiles, in the USGS webpage you can get some crops of the zone you want to use, it's better to use this source if you are using small zones or your zone is in between several tiles, with the Google Earth layer you can also get tiles, and in several formats as ARCASCII or GeoTiff.