SRTM: Shuttle Radar Topographic Mission - CIAT V4

 
 

The Joint Research Center (together with the International Center for Tropical Agriculture, Colombia) provides processed SRTM 90m Digital Elevation Data for the entire world. The data on this website mirrors the data available at http://srtm.csi.cgiar.org/. The SRTM digital elevation data, originally produced by NASA, is a major breakthrough in digital mapping of the world, and provides a major advance in the accessibility of high quality elevation data for large portions of the tropics and other areas of the developing world. The SRTM digital elevation data provided on this mirror has been processed to fill data voids, and to facilitate it's ease of use by a wide group of potential users. This data is provided in an effort to promote the use of geospatial science and applications for sustainable development and resource conservation in the developing world. Please use http://srtm.csi.cgiar.org/ to search on your area of interest.

Digital elevation models (DEM) for the entire globe, covering all of the countries of the world, are available for download on this site. The SRTM 90m DEM's have a resolution of 90m at the equator, and are provided in mosaiced 5 deg x 5 deg tiles for easy download and use. All are produced from a seamless dataset to allow easy mosaicing. These are available in both ArcInfo ASCII and GeoTiff format to facilitate their ease of use in a variety of image processing and GIS applications. Data can be downloaded using a browser or accessed directly from the ftp site. The DEM data on this site are Version 3 of the CSI-SRTM data with included improved clipping of shorelines using the SRTM Water Bodies Data (SWBD), and improved interpolation of voids areas (using high resolution auxiliary data for US, Canada, Mexico, Europe, Australia, New Zealand and GTOPO30 global topographic data for other areas). If you find this digital elevation data useful, please let us know at srtm ad jrc.it or csi ad cgiar.org.

The NASA Shuttle Radar Topographic Mission (SRTM) has provided digital elevation data (DEMs) for over 80% of the globe. This data is currently distributed free of charge by USGS and is available for download from the National Map Seamless Data Distribution System, or the USGS ftp site. The SRTM data is available as 3 arc second (approx. 90m resolution) DEMs. A 1 arc second data product was also produced, but is not available for all countries. The vertical error of the DEM's is reported to be less than 16m. The data currently being distributed by NASA/USGS (finished product) contains "no-data" holes where water or heavy shadow prevented the quantification of elevation. These are generally small holes, which nevertheless render the data less useful, especially in fields of hydrological modeling.

Dr. Andrew Jarvis and Edward Guevara of the Center for International Tropical Agriculture - Land Use project, Dr. Hannes Isaak Reuter (JRC-IES-LMNH) and Dr. Andy Nelson (JRC-IES-GEM), have further processed the original NASA DEMs to fill in these no-data voids. This involved the production of vector contours, and the re-interpolation of these derived contours back into a raster DEM. The method allows for (i) the support for auxiliary information, (ii) the use of a void region specific processing over a tile based processing, (iii) use of SWDB V2 water body database, (iv) correction for vertical bias, (v) for areas with auxiliary high resolution DEM information a hydrologically correct DEM is generated based on the TOPOGRID procedure, (vi) for areas without a high resolution auxiliary DEM the most appropriate interpolation technique is selected based on void size and landform typology according to Reuter et al.(2007).

These interpolated DEM values were then used to fill in seamlessly the no-data holes within the SRTM data. This was done using Arc/Info(R) and an AML script. The DEM files have been mosaiced into a seamless global coverage, and are available for download as 5 degree x 5 degree tiles, in geographic coordinate system - WGS84 horizontal and EGM96 vertical datum. These files are available for download in both Arc-Info ASCII format, and as GeoTiff, for easy use in most GIS and Remote Sensing software applications. In addition, a binary no data mask file is available for download, allowing users to identify the areas within each DEM which has been interpolated.

We kindly ask any users to cite this data in any published material produced using this data. Please cite the dataset for the Version 4 as: Jarvis A., H.I. Reuter, A. Nelson, E. Guevara, 2008, Hole-filled seamless SRTM data V4, International Centre for Tropical Agriculture (CIAT), available from http://srtm.csi.cgiar.org.

Rules of DISTRIBUTION: Users are prohibited from any commercial, non-free resale, or redistribution without explicit written permission from CIAT. Users should acknowledge CIAT as the source used in the creation of any reports, publications, new data sets, derived products, or services resulting from the use of this data set. CIAT also request reprints of any publications and notification of any redistributing efforts. NO WARRANTY OR LIABILITY: CIAT/JRC provides these data without any warranty of any kind whatsoever, either express or implied, including warranties of merchantability and fitness for a particular purpose. CIAT/JRC shall not be liable for incidental, consequential, or special damages arising out of the use of any data.