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Description
The Land Processes Distributed Active Archive Center (LP DAAC) is responsible for the archive and distribution of NASA Making Earth System Data Records for Use in Research Environments (MEaSUREs) SRTM, which includes the global 3 arc second (~90 meter) product. The 3 arc second data was derived from the 1 arc second using averaging methods. (See Figure 3 in the User Guide)
The NASA SRTM data sets result from a collaborative effort by the National Aeronautics and Space Administration (NASA) and the National Geospatial-Intelligence Agency (NGA - previously known as the National Imagery and Mapping Agency, or NIMA), as well as the participation of the German and Italian space agencies. This collaboration aims to generate a near-global digital elevation model (DEM) of Earth using radar interferometry. SRTM was the primary (and virtually only) payload on the STS-99 mission of the Space Shuttle Endeavour, which launched February 11, 2000 and flew for 11 days.
The SRTM swaths extended from ~30 degrees off-nadir to ~58 degrees off-nadir from an altitude of 233 kilometers (km), creating swaths ~225 km wide, and consisted of all land between 60° N and 56° S latitude to account for 80% of Earth's total landmass.
The SRTMGL3 data were generated from SRTM1GL data that fall within that tile. These elevation files use the extension ".HGT", meaning height (such as N37W105.SRTMGL3.HGT). The primary goal of creating the Version 3 data was to eliminate gaps, or voids, that were present in earlier versions of SRTM data. In areas with limited data, existing topographical data were used to supplement the SRTM data to fill the voids. The source of each elevation pixel is identified in the corresponding SRTMGL3N product (such as N37W105.SRTMGL3N.NUM).
The global 3 arc second SRTM product is also available in NetCDF4 format as the SRTMGL3_NC dataset with the source of each elevation pixel in the corresponding SRTMGL3_NUMNC product.
Known Issues
Known issues in the NASA SRTM are described in the following publication:
Rodriguez, E., C. S. Morris, and J. E. Belz (2006), A global assessment of the SRTM performance, Photogramm. Eng. Remote Sens., 72, 249–260. https://doi.org/10.14358/PERS.72.3.249
Version Description
The following improvement was implemented for SRTM Version 3 data products: Missing data or voids were filled with ASTER Global Digital Elevation Model (GDEM) Version 2, the Global Multi-resolution Terrain Elevation Data 2010 (GMTED2010), or the National Elevation Dataset (NED).
Citation is critically important for dataset documentation and discovery. This dataset is openly shared, without restriction, in accordance with the EOSDIS Data Use and Citation Guidance.
Copy Citation
Citation Copied
NASA JPL. (2013). NASA Shuttle Radar Topography Mission Global 3 arc second [Data set]. NASA Land Processes Distributed Active Archive Center. https://doi.org/10.5067/MEASURES/SRTM/SRTMGL3.003 Date Accessed: 2026-05-24
NASA JPL. “NASA Shuttle Radar Topography Mission Global 3 Arc Second.” NASA Land Processes Distributed Active Archive Center, 2013. doi:10.5067/MEASURES/SRTM/SRTMGL3.003. Date Accessed: 2026-05-24
NASA JPL. NASA Shuttle Radar Topography Mission Global 3 Arc Second. NASA Land Processes Distributed Active Archive Center, 2013, doi:10.5067/MEASURES/SRTM/SRTMGL3.003. Date Accessed: 2026-05-24
File Naming Convention
N00E109.hgt
The file name begins with the latitude and longitude of the lower left corner of the tile (N00E109) followed by the Data Format (hgt).