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SRTM Datasets
Shuttle Radar Topography Mission (SRTM) elevation datasets can be used to supplement our NEXTMap® high-resolution datasets while we complete the collection and building of our national elevation database of countries around the world. We have taken SRTM elevation data and packaged it into neat, functional, countrywide digital elevation and shaded relief products.
These products are available for purchase by a country or group of countries (except for the United States, which is broken into states and territorial islands). Two products are offered:
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| | The products are derived from National Geospatial-Intelligence Agency and National Aeronautics and Space Administration's SRTM data supplied by the U.S. Geological Survey. The U.S. state and territorial island models are clipped from SRTM DTED® Level 2 data using ESRI's shapefiles of U.S. state boundaries. The country models are clipped from the SRTM DTED® Level 1 data by using ESRI's international country shapefiles. | |
Features
- Whole-country (or U.S. state) datasets
- National boundaries buffered 12 nautical miles to include most international maritime limits*
- Ocean elevation set to 0 meters
- Lakes of 600 meters or more in length flattened
- Available in geographic coordinates (WGS84 Datum)
- Elevations referenced to mean sea level, as determined by the WGS84 Earth Gravitational Model (EGM 96)
- Available in ESRI GRID format
- Post spacing of DTED data defined in arc-seconds
- DTED 1 data has a post spacing of 3 arc-seconds (about 90m at the equator)
- DTED 2 data has a post spacing of 1 arc-second (about 30m at the equator)
* The 12 mile buffer limits may vary depending on 1) the inclusion or exclusion of island features in the SRTM data outside of the ESRI 2004 country/U.S. state shapefile and 2) the extent of available SRTM DTED data coverage.
Accuracy
Absolute accuracy of the products is dependent upon the quality of the source SRTM data and the production methodology.
- Absolute horizontal accuracy for both Level 1 and 2 DTED of 90% circular error < 20 meters
- Absolute vertical accuracy for both Level 1 and 2 DTED of 90% circular error < 16 meters
Federal Geographic Data Committee (FGDC) compatible metadata files are provided with each product, including information on the production methodology and product accuracy.
For more information, contact an Intermap representative via telephone at 1-877-837-7246 (US and Canada), +49 (0) 89-309-0799-0 (Europe), +62 21 719 3808 (Southeast Asia and Australia), or via e-mail at products@intermap.com.
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