SRTM US Digital Elevation Model at 1 Arc-Second Resolution

NASA Shuttle Radar Topography Mission United States 1 arc second data provides a digital elevation model (DEM) for the contiguous United States at approximately 30-meter resolution. The dataset was generated from radar interferometry data collected during the Space Shuttle Endeavour's 11-day STS-99 mission in February 2000. This collection was retired in November 2014, with its data now incorporated into the global SRTMGL1 product.

Use Cases

• Terrain analysis and slope calculation using the elevation values in .HGT files.
• Hydrological modeling to delineate watersheds and flow accumulation from the DEM.
• Creating topographic relief maps and 3D visualizations of the US landscape.
• Filling voids in other elevation datasets by referencing the supplementary source data identified in the SRTMUS1N product.
• Validating and calibrating newer global DEM products against this foundational US dataset.

Strengths

• Data voids were eliminated in Version 3 by supplementing with existing topographical data.
• Elevation values are a mosaic generated by averaging multiple radar 'data takes' for each tile.
• Produced through a collaborative effort by NASA, NGA, and German and Italian space agencies.
• Collected from a consistent altitude of 233 kilometers with swaths extending from ~30 to ~58 degrees off-nadir.

Limitations

• The dataset is retired and has been superseded by the global SRTMGL1 product since November 2014.
• Specific row counts, column names, and total dataset size are not provided across any source.
• There is a conflict in the 'last updated' date: datagov lists 2026-03-12, while nasa_earthdata lists 2000-02-21.

Provenance

Source

National Aeronautics and Space Administration (NASA), National Geospatial-Intelligence Agency (NGA), with participation from German and Italian space agencies.

Collection Method

Radar interferometry data collected from the Space Shuttle Endeavour during its STS-99 mission, with elevations generated by averaging and blending all 'data takes' within each tile.

Time Range

Data collected during the 11-day mission launched on February 11, 2000.

Freshness

2026-03 12 23:28:23.283414

Geography

Contiguous United States.