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Description
The Land Processes Distributed Active Archive Center (LP DAAC) is responsible for the archive and distribution of the NASA Making Earth System Data Records for Use in Research Environments (MEaSUREs) version SRTM, which includes the global 1 arc second (~30 meter) product.
NASA Shuttle Radar Topography Mission (SRTM) datasets 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. The purpose of SRTM was to generate a near-global digital elevation model (DEM) of the Earth using radar interferometry. SRTM was a primary component of the payload on the Space Shuttle Endeavour during its STS-99 mission. Endeavour launched February 11, 2000 and flew for 11 days.
SRTM collected data in swaths, which extend from ~30 degrees off-nadir to ~58 degrees off-nadir from an altitude of 233 kilometers (km). These swaths are ~225 km wide, and consisted of all land between 60° N and 56° S latitude. This accounts for about 80% of Earth's total landmass.
Each SRTMGL1 data tile contains a mosaic and blending of elevations generated by averaging all "data takes" that fall within that tile. These elevation files use the extension ".HGT", meaning height (such as N37W105.SRTMGL1.HGT). The primary goal of creating the Version 3 data was to eliminate 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 SRTMGL1N product (such as N37W105.SRTMGL1N.NUM).
The global 1 arc second SRTM product is also available in NetCDF4 format as the SRTMGL1_NC dataset with the source of each elevation pixel in the corresponding SRTMGL1_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 1 arc second [Data set]. NASA Land Processes Distributed Active Archive Center. https://doi.org/10.5067/MEASURES/SRTM/SRTMGL1.003 Date Accessed: 2026-04-30
NASA JPL. “NASA Shuttle Radar Topography Mission Global 1 Arc Second.” NASA Land Processes Distributed Active Archive Center, 2013. doi:10.5067/MEASURES/SRTM/SRTMGL1.003. Date Accessed: 2026-04-30
NASA JPL. NASA Shuttle Radar Topography Mission Global 1 Arc Second. NASA Land Processes Distributed Active Archive Center, 2013, doi:10.5067/MEASURES/SRTM/SRTMGL1.003. Date Accessed: 2026-04-30
File Naming Convention
N26W077.hgt
The file name begins with the latitude and longitude of the lower left corner of the tile (N26W077) followed by the Data Format (hgt).
SRTMGL1 coverage now includes Africa, Europe, North America, South America, Asia, and Australia in 1° X 1° tiles at 1 arc second (about 30 meters) resolution.
The table below lists the variables contained within a single granule for this
dataset. Variables often contain observed or derived geophysical measurements
collected from a variety of sources, including remote sensing instruments on
satellite and airborne platforms, field campaigns, in situ measurements, and
model outputs. The terms variable, parameter, scientific data set, layer, and band
have been used across NASA’s Earth science disciplines; however, variable is the
designated nomenclature in NASA’s Common Metadata Repository (CMR).
Variable metadata attributes such as Name, Description, Units, Data Type, Fill
Value, Valid Range, and Scale Factor allow users to efficiently process and analyze
the data. The full range of attributes may not be applicable to all variables.
Additional information on variable attributes is typically available in the data,
user guide, and/or other product documentation.
For questions on a specific variable, please use the Earthdata Forum.
