Shuttle Radar Topographic Mission Digital Elevation Model (SRTM)

 The Shuttle Radar Topography Mission (SRTM) database contains global elevation data with 3 arc-second (90 m) spatial resolution.  The data are made available through the CGIAR Consortium for Spatial Information (CGIAR-CSI) website in mosaiced 5 deg x 5 deg tiles in both ArcInfo ASCII and GeoTiff format. GIS software, commercial or public-access, is needed for data visualization and further processing or combination with other spatial datasets. The vertical error of the digital elevation model (DEM) is reported to be less than 16m. The original data distributed by NASA/USGS contained “no-data” holes where water or heavy shadow prevented the quantification of elevation. The 90 m dataset distributed by CGIAR-CSI is an improved global DEM in which the no-data voids of the original DEMs have been filled-in.

A 1 arc-second (30 m) global dataset also exists, but void-filling at this resolution has only been undertaken consistently for the USA.