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Mangroves (dark green) along the Ord River in Australia, with sediment and nutrients swirling through the estuary, in a Landsat 8 image from May 12, 2013. The bright spot at lower left is mudflats, home to saltwater crocodiles. USGS.
A permanent record of the land
The National Satellite Land Remote Sensing Data Archive (NSLRSDA) is run for the Secretary of the Interior by the U.S. Geological Survey's Earth Resources Observation and Science (EROS) Center.
- Why: the Land Remote Sensing Policy Act of 1992 told the Department of the Interior to build a permanent global archive of satellite images of the Earth's land, and to store, preserve and make them available to everyone in good time.
- Cost: since 2008, the images have been free.
Why it matters
The archive gives an unbiased view of the land surface from the 1960s to today.
- Comparing early and recent images reveals change, how fast it happens, and trends in land use and environmental processes worldwide.
- It supports science, environmental monitoring, agriculture and natural resource management, and disaster management.
- Before-and-after images spanning decades inform science, policy and action, at local, regional and global scales.
- Many collections complement each other; combining them helps researchers study environmental change, energy and mineral resources and much more.
San Diego, California, in 1970, from the declassified Declassification I collection. USGS.
What's in it
The archive holds film and digital records from the 1960s on. They can never be recreated: each captured the land on one day in history. Detail (ground resolution) ranges from under 1 meter to 1,000 meters — smaller numbers mean more detail. (One meter is about 39.4 inches.)
| Collection | Years | Ground resolution |
|---|---|---|
| Declassification I | 1960–72 | 2–153 m |
| Declassification II | 1963–80 | 0.6–10 m |
| Declassification III | 1971–84 | 0.6–9.1 m |
| Gemini | 1965–66 | 50–125 m |
| Skylab | 1973–74 | 22–99 m |
| Large Format Camera | 1984 | 10–15 m |
| Landsat Multispectral Scanner | 1972–92 | 80 m |
| Landsat Thematic Mapper | 1982–2012 | 30 m |
| Landsat Enhanced Thematic Mapper Plus | 1999–present | 15 or 30 m |
| Landsat Operational Land Imager | 2013–present | 15 or 30 m |
| Landsat Thermal Infrared Sensor | 2013–present | 100 m |
| Landsat Orthoimagery | 1972–2003 | 15–80 m |
| Global Land Surveys | 1972–2011 | 15–80 m |
| Système Pour l'Observation de la Terre (SPOT) | 1986–98 | 10 or 20 m |
| Advanced Very High Resolution Radiometer | 1980–present | 1,000 m |
| Shuttle Radar Topography Mission | 2002 | 30 m |
| GeoEye OrbView–3 | 2003–2007 | 1 or 4 m |
Collections as of 2018.
How to get the data
- About the archive: eros.usgs.gov/nslrsda.
- Search and download: EarthExplorer, the main access system.
- Questions: USGS EROS Center Customer Services, 47914 252nd Street, Sioux Falls, SD 57198–0001; 800–252–4547 or 605–594–6151; custserv@usgs.gov; Monday–Friday, 8 a.m. to 4 p.m. Central time.
Sources
Based on National Satellite Land Remote Sensing Data Archive, USGS Fact Sheet 2018–3027 (June 2018), by John L. Faundeen and Ryan Longhenry, U.S. Geological Survey; a work of the United States government in the public domain. The images and table are taken from the fact sheet's PDF; its 1986 SPOT and 2007 OrbView–3 images of San Diego, from commercial satellites, are not reproduced.
Licence : CC0 1.0 (domaine public) · Adapté de pubs.usgs.gov
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