The Shuttle Radar Topography Mission–a new source of near-global digital elevation data

Abstract

The Shuttle Radar Topography Mission (SRTM) has generated a homogeneous near-global digital elevation model (DEM) of the Earth using single-pass radar interferometry. The crew of Space Shuttle Endeavour (STS-99) operated the modified dual-antenna synthetic aperture radar systems for 11 days in February 2000. SRTM acquired both C-band and X-band synthetic aperture radar data, collecting 3D data using a 60-metre mast extending from the shuttle payload bay, containing additional C-band and X-band receiver antennas. SRTM DEM data have a horizontal resolution of 1 arc second (30 m at the equator) and vertical resolution of 10 m (C-band radar). SRTM-1 (1 arc second) data are available for US territories only, with subsampled SRTM-3 (3 arc second) data provided for the rest of the world. The USGS is responsible for archiving the data, with 3 arc second data being made freely available on a continent-by-continent basis. All data processing was completed in July 2004. Comparison of SRTM DEM data with older GTOPO and altimetric DEMs shows a significant improvement in horizontal and/or vertical resolution, similar to that achieved by ASTER. The SRTM DEM data provide a useful new resource, especially in areas where limited topographic data are available.