The SRTM X-SAR Elevation Mosaic is an aggregation of DLR's SRTM X-SAR DTED files. The DTED Level-2 files have been generated from Synthetic Aperture Radar (SAR) data acquired by the German-Italian X-band interferometric SAR system during the Shuttle Radar Topography Mission (SRTM) between February 11 and 22, 2000. The X-band system was flown and operated onboard the Space Shuttle Endeavor, along with a NASA C-Band SAR system. The SRTM project page at DLR provides additional information on the SRTM X-band mission ( http://www.dlr.de/caf/en/desktopdefault.aspx/tabid-5515 /9214_read-17716/ ). Further details on the mission in general, the technology, accuracies, and applications are available in http://www2.jpl.nasa.gov/srtm/SRTM_paper.pdf . The original DTED files have been grouped and mosaicked into 30 x 30 degree tiles. Six out of the total of 48 tiles were empty since they do not contain any DTED files. The resulting 42 tiles are stored as uncompressed GeoTIFF files. The files have been supplemented with nine cubic convolution resampled overviews for fast web delivery.

The SRTM X-SAR Hillshade Mosaic is a greyscale shaded relief based on the SRTM X-SAR Elevation Mosaic. Combined with the latter, it can be used to add a 3d effect and enhance the visual resolution by pronouncing peaks and valleys.

The SRTM X-SAR Error Mosaic is based on the height error map (HEM, see SRTM PDF http://www.dlr.de/eoc/Portaldata/60/Resources/dokumente/7_sat_miss/SRTM-XSAR-DEM-DTED-1.1.pdf) and provides a local measure of the achieved accuracy. It is statistically determined from a neighborhood of image cells mainly considering the phase and baseline stability. Thus it describes the precision relative to the surrounding. The determination of the absolute accuracy requires the consideration of reference measures.