| SRTM data sets result from a collaborative effort by NASA and NGA, as well as the participation of the German and Italian space agencies to generate a near-global digital elevation model of the Earth using radar interferometry. Sometimes referred to as "90 meter" data, the sample spacing of SRTM3 for individual data points is 3 arc-seconds. Version 2 of the SRTM digital topographic data (also known as the "finished" version) is the result of a substantial editing effort by the NGA and exhibits well-defined water bodies and coastlines and the absence of spikes and wells (single pixel errors), although some areas of missing data ('voids') are still present. The default file format for SRTM data is .HGT; After selecting desired tiles, customers may choose a variety of industry-standard georeferencing and formatting options. The SRTM-3 is a cost-effective choice for many applications. |