Figure 1. Changes to the land from surface mining can be seen in eastern Kentucky 

(Breathitt, Knott, and Perry Counties), as depicted by comparing elevation from the 

National Elevation Dataset (NED; left, predisturbance) and SRTM data (right, postdisturbance, mining area in middle of image). The NED data are derived from topographic map 

data compiled in 1952. The SRTM data were collected in February 2000. This perspective 

view, looking to the northeast, covers an area of about 37 square miles.

U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2009–3087

September 2009

Shuttle Radar Topography Mission (SRTM)

Artist’s rendering of Space shuttle Endeavour and the 200-foot long 

SRTM antenna deployed for image acquisition.

ackground

Under an agreement with the National Aeronautics 

and Space Administration (NASA) and the Department 

of Defense’s National Geospatial-Intelligence Agency 

(NGA), the U.S. Geological Survey (USGS) is distributing 

elevation data from the Shuttle Radar Topography Mission (SRTM). The SRTM is a joint project of NASA and 

NGA to map the Earth’s land surface in three dimensions 

at an unprecedented level of detail. As part of space shuttle 

Endeavour’s flight during February 11–22, 2000, the 

SRTM successfully collected data over 80 percent of the 

Earth’s land surface for most of the area between latitudes 

60 degrees north and 56 degrees south. The SRTM hardware included the Spaceborne Imaging Radar-C (SIR–C) 

and X-band Synthetic Aperture Radar (X–SAR) systems 

that had flown twice previously on other space shuttle 

missions. The SRTM data were collected with a technique 

known as interferometry that allows image data from dual 

radar antennas to be processed for the extraction of ground 

heights.

Data

NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California, processed more than 12 terabytes of 

raw SRTM data into preliminary, research-quality digital elevation models on a continent-by-continent basis. 

NGA completed editing, verifying, and reformatting of 

the preliminary data by the end of September 2004. The 

USGS Earth Resources Observation and Science (EROS) 

Applications

Elevation data are used for many applications and three-dimensional visualizations 

of the Earth’s surface. The earth science community regularly uses products like SRTM 

data for hydrologic and geologic investigations. The SRTM dataset represents a recent 

snapshot of the Earth’s land surface that can 

be compared to historical elevation data to 

assess changes to the landscape, as illustrated 

in figures 1 and 2. Satellite image data can 

be combined with SRTM elevation data for 

visualizations of the land surface.

Center in Sioux Falls, South Dakota, is the long-term archive for 

SRTM data and provides these data to the general public and the 

science community. Data available to the geospatial data user 

community include 1-arc-second (about 30-meter) resolution 

data over the United States and its territories, and 3-arc-second 

(about 90-meter) data over non-U.S. territory. The SRTM data 

complements other elevation data available from the USGS 

EROS Center.

B
Figure 2. Interstate 68 road cut in western 

Maryland, as depicted by comparison of 

NED data (left, preconstruction) and SRTM 

data (right, postconstruction, I–68 road cut 

in middle of image). The maximum depth of 

the road cut through the ridge is 322 feet. The 

NED data were derived from topographic 

map data compiled in 1947. The SRTM data 

were collected in February 2000. This view 

covers an area of about 15 square miles.

Data Access

Perspective view of Kamchatka Peninsula, Russia. The view, looking to the east, 

shows a 20-mile-wide expanse of the 

Russian coastline with the Sea of Okhotsk 

in the foreground (Landsat 7 and SRTM). 

The Landsat 7 data were acquired in 

August 1999.

Pre-eruption perspective view of the 

Nyiragongo, Congo, volcano (peak on the 

right). This 13-mile-wide view, looking to 

the northeast, shows the city of Goma on 

the shore of Lake Kivu in the foreground 

(Landsat 7 and SRTM). The Landsat 7 data 

were acquired in December 2001.

Perspective view of Mount Etna, Italy 

[Advanced Spaceborne Thermal Emission 

and Reflection Radiometer(ASTER) and 

SRTM], looking to the south. The ASTER 

data were acquired in July 2001.

For additional information, please contact 

U.S. Geological Survey 

Earth Resources Observation and Science (EROS) Center 

47914 252nd Street 

Sioux Falls, SD 57198-0001 

Phone: 605-594-6151 

Fax: 605-594-6589 

E-mail: lta@usgs.gov

Further Information

z Information about the Land Remote Sensing 

Program is available at http://remotesensing.usgs.gov.

z For further information about the SRTM and radar 

interferometry, visit the NASA Web site at

http://www2.jpl.nasa.gov/srtm/

For information on other USGS products and services, call 

1-888-ASK-USGS, or visit the general interest publications 

Web site on mapping, geography, and related topics at 

http://erg.usgs.gov/publications.html.

For additional information, visit “Ask USGS” at http://ask.usgs.

gov or the USGS home page at http://www.usgs.gov.

Related datasets from USGS EROS Center include the 

following:

• National Elevation Dataset (NED) 

http://ned.usgs.gov/

• Elevation Derivatives for National Applications (EDNA) 

http://edna.usgs.gov

• Global 30-Arc-Second Elevation Dataset (GTOPO30) 

http://eros.usgs.gov/products/elevation/gtopo30.html

• HYDRO1k Elevation Derivative Database 

http://eros.usgs.gov/products/elevation/hydro1k.html

The SRTM finished products are available in ArcGrid, GRIDFLOAT, BIL, and Tiff format. Data are available through the USGS Seamless Data Distribution System 

(SDDS; http://seamless.usgs.gov) and EarthExplorer (http://

earthexplorer.usgs.gov). The SRTM 1-arc-second coverage 

includes the conterminous United States, southern Alaska, 

Hawaii, and island territories. The global SRTM 3-arcsecond data are also available through the SDDS. These 

data are available at no cost via download. Information on 

how to search and download these data can be found at the 

USGS EROS elevation page: http://eros.usgs.gov/products/

elevation/.