Elevation models from SRTM now available for download free of charge
DLR is now making the data collected on a Shuttle flight in February 2000 available for scientific purposes via EOWEB, free of charge.
During the mission, the radars allowed researchers to obtain elevation data regardless of the time of day and weather conditions. The flight path of Endeavour dictated the areas imaged by the radars; the SRTM data covered regions with latitudes between 60 degrees north and about 60 degrees south – the polar regions were inaccessible. DLR used an X-band radar to cover a smaller area, but with a precision of plus or minus six metres. "The accuracy of these global elevation models has yet to be surpassed," said Dech. This explains why, eleven years later, many researchers are still using these datasets.
The X-band DEMs from the SRTM mission have resolution of one arcsecond, corresponding to a pixel size of 25 metres at central latitudes. Each DEM covers an area of 2.5 by 2.5 degrees and is composed of 100 'tiles', each measuring 15 arcminutes by 15 arcminutes (900 by 900 data points). They can be downloaded free of charge by registering with EOWEB. Registered users can download these datasets from an FTP server. SRTM data can be incorporated directly into digital maps or geographical information systems by means of a standardised Web Map Service (WMS).