Earth Resources Observation and Science (EROS) Center
Welcome to the USGS EROS Center
Welcome to the U.S. Geological Survey (USGS) Earth Resources Observation and Science (EROS) Center Virtual Tour. We’ll take you around the Center and even share a few sneak peeks of behind-the-scenes activities.
EROS was established in 1971 to receive, process, and distribute data from the Landsat series of Earth-observing satellites, as well as aerial photographs gathered for the USGS and other agencies. The original 115,000-square-foot building was completed in 1973. In March 1996, the Center completed a 65,000-square-foot addition to house equipment and people for NASA’s Earth Observing System Program and Landsat 7 data handling.
Elements of our work potentially affect millions of lives. We supply data—the raw material of science—to a worldwide community of users. Scholars, engineers, and land managers use our data to study a growing list of environmental issues such as resource development, global change, and land use planning. In addition to maintaining earth science data, EROS scientists constantly work to discover new ways to use this information.
Image: The entrance of the USGS EROS Center.
Unlike most other Federal institutions, the EROS staff consists of Federal civil servants and private contractors. Of the more than 600 employees at EROS, about 140 work for the government and the rest work for contractors. The staff at EROS receives, processes, studies, and distributes many types of land science information from various sources.
EROS employees manage an archive of more than 4 million satellite images spanning 40 years and more than 8 million aerial photos dating back to the 1930s. They continually keep track of the changing surface of the Earth.
Through scientific research, data management, software and system engineering, IT and computer operations, and customer service, EROS employees
Contribute to the understanding of a changing Earth through research to operations activities that include developing, implementing, and operating remote sensing based terrestrial monitoring capabilities needed to address science and applications objectives at all levels – within the USGS, across the Federal government, and around the world. The EROS multidisciplinary staff uses their unique expertise in remote sensing-based science and technologies to carry out basic and applied research, data acquisition, systems engineering, information access and management, and archive preservation to address the Nation’s most critical needs.
—USGS EROS Strategic Plan 2010–2015
Image: The lobby at the USGS EROS Center.
Why is EROS in Sioux Falls, South Dakota?
In the 1960s, when the idea for the EROS project was first discussed, a study determined the best location for handling and distributing satellite data. The report recommended that such a data center be located where it could receive transmissions directly from a satellite passing over any part of the conterminous United States. This limited the location to an elliptical area that stretched from Topeka, Kansas, to just north of Sioux Falls. A rural location was also recommended to avoid radio and TV interference.
South Dakota Senator Karl Mundt worked with business leaders in Sioux Falls to raise money to buy land north of Sioux Falls. The group then donated the land to the government, which helped persuade the USGS to choose the South Dakota location.
Image: This map shows the recommmended area for a data center to be located.
What is remote sensing?
What is remote sensing? Remote sensing is the process of obtaining information about an object without touching it. Some everyday examples of remote sensing devices include cameras, telescopes, and your very own eyes!
When the Sun shines on Earth, the structures and vegetation on the surface absorb and reflect some of the Sun’s energy. The absorbed and reflected energy is detected by the satellite in different wavelengths in the electromagnetic spectrum. Remote sensing devices on Earth-observing satellites acquire data in the visible, infrared, and thermal infrared portions of the electromagnetic spectrum. The data from these different wavelengths of the spectrum are combined in different ways to create false color images.
Image: A false color image of Phoenix, Arizona.
A camera from the space shuttle Challenger (1984)
The Large Format Camera was a remote sensing system used during a mission aboard space shuttle Challenger in October 1984. Engineers designed this device to shoot photographs for precision mapping projects involving the exploration of minerals and fossil fuels such as oil and coal.
Image: The Large Format Camera on display at EROS is not a model—this camera that was actually in space!
Sioux Falls over time
The series of aerial images of Sioux Falls demonstrates the theme of tracking change over time. Scientists use land imaging information from satellites and aerial photos to monitor how the earth’s landscape changes throughout the decades. Monitoring changes to cities is important for planning their future growth.
Image: A series of aerial photos shows how Sioux Falls has changed over time.
Scanning millions of frames of aerial imagery
The 8 million frames of aerial film imagery in the USGS film archive collections are being systematically scanned to a standard format high resolution. These digital scans are added to the vast archive at EROS and made available for download to the public at no charge.
The scanning systems that scan these images were designed and built at EROS. (You won’t get to see this on the real tour!)
Image: A technician sets up a scanning system to digitize a roll of aerial film.
Landsat satellite imagery
EROS receives, archives, and distributes images from the Landsat series of satellites. The first Landsat satellite was launched in 1972. It was soon followed by Landsats 2, 3, and 4. Landsat 5 launched in 1984 and operated until November 2011. It was decommissioned in early 2013. Landsat 7 launched in 1999 and continues to operate. Landsat 8 launched from Vandenberg Air Force Base in California on February 11, 2013.
Image: The launch of Landsat 8 on February 11, 2013.
Landsat 8 ensures that the Landsat mission continues. It acquires and makes available Landsat-like data at a scale where natural and human-induced changes can be detected and monitored over time. Its design life is 5 years, but it contains enough fuel to operate for 10 years.
Image: An artist’s rendition of Landsat 8.
The state of South Dakota display
This false color map of South Dakota is a mosaic of Landsat images. Healthy vegetation appears red, so the dark red on the left is easy to identify as the Black Hills. Cultivated fields are also dispersed throughout the state.
Image: The South Dakota Landsat mosaic.
What are digital satellite images made of?
A digital satellite image is made up of picture elements called pixels. Arranged horizontally and vertically, each pixel represents the minimum size of an area on the ground that is detectable by a remote sensing device. The resolution of a Landsat image is 30 meters, so each pixel represents a square 30 meters by 30 meters, a little bigger than a baseball diamond.
Image: A satellite image is made up of pixels.
Behind the scenes - Computer Room II
EROS operates two of the largest computer complexes within the Department of the Interior. The USGS uses EROS’ resources to put ever greater amounts of earth science data online.
Image: The computer room at EROS where satellite images are processed.
Behind the scenes – downlinking satellite data
EROS downlinks data directly from the operational Landsat satellites. Visit EarthNow to see real-time data from Landsat over North America.
Image: A behind-the-scenes view of an engineer monitoring Landsat data as it is received.
Protecting the antennas
Behind the Center are two radomes that house antennas. These antennas collect the data directly from the Landsat satellites as they pass over North America. The radomes protect the antennas from rain, sleet, snow, ice, and wind up to 150 miles per hour.
Image: Radomes protect the antennas from the elements.
Behind the scenes - a 10-meter antenna
Inside the larger radome is a 10-meter antenna. It can move automatically to track the satellite as it passes over North America.
Image: A sneak peek inside one of the radomes shows one of the antennas that collect the satellite data.
Behind the scenes – storing data at EROS
The data from satellites and other remote sensing sources are written to tape cartridges. These tapes, more reliable and cost-effective than CDs or disks, are backed up and stored in a mass storage system for robotic retrieval. The current amount of data in the archive at EROS is more than 5 petabytes. But the mass storage system has the capacity to hold 45 petabytes, so we have room for more. Servers also make much of the satellite information immediately available to scientists worldwide.
Image: One of the mass storage systems at EROS.
Landsat ground stations
In addition to EROS, several ground stations worldwide downlink and distribute Landsat data. The circles show the approximate area over which each station has the capability for direct reception of Landsat data. Many of these stations contribute to the USGS Landsat archive.
Image: A network of ground stations collects Landsat data.
NASA imagery at EROS
EROS also houses part of NASA’s Earth Science Data and Information System (ESDIS). The Land Processes Distributed Active Archive Center (LP DAAC) ingests, processes, archives, and distributes imagery from NASA’s Terra and Aqua satellites.
The data from these satellites are from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor onboard Aqua and the MODIS and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) sensors onboard Terra. EROS distributes about 3 terabytes of data every day from this collection.
The data from ASTER are used to make detailed maps of the Earth’s surface temperature, study meteorology and climate change, and provide information for disaster relief efforts. MODIS is designed to study large-scale changes such as fires, ash plumes from volcanoes, and vegetation patterns.
Image: An artist’s rendition of the Terra satellite.
LP DAAC - ASTER
This ASTER image shows a wildfire in the San Bernardino Mountains of California. In this false color image, vegetation is green, burned areas are reddish, and smoke is blue.
Image: This ASTER image of the San Bernardino fire was acquired October 26, 2003.
LP DAAC - MODIS
This MODIS image shows tropical cyclone Izilda off the west coast of southern Madagascar. Cyclone Izilda had estimated winds of 40 miles per hour, and the storm intensified when it made landfall.
Image: This MODIS Image of Cyclone Izilda was acquired March 25, 2009.
The National Land Cover display at EROS
The National Land Cover Database 2001 (NLCD 2001) display shows the land cover of the United States based on Landsat data from 2001. The color-coded map indicates where there are wetlands, forests, croplands, urban areas, and other types of land cover. NLCD 2001 also includes specific products that measure tree canopy density and urban impervious surface density. Scientists use the database to track changes to the landscape over time.
Image: The National Land Cover Database.
The lidar display at EROS
Lidar is an optical remote sensing technology used to determine the distance of a target from the sensor by measuring some of the basic properties of a reflected laser light pulse, such as intensity and timing. Lidar is especially useful in detecting small changes in land elevation.
The lidar display of an image over Sioux Falls, South Dakota, shows how detailed lidar elevation data can be as we can see the interstates, golf courses, airport runways, and even houses and trees.
Image: Lidar image of Sioux Falls, South Dakota.
The National Elevation display at EROS
The National Elevation Dataset (NED) is a 3D representation of elevation in the United States. NED is composed of 10-meter and high resolution 3-meter elevation data derived from lidar. NED data can be used to study the shape of the ground surface, which helps scientists model the direction of streamflow over the land.
Image: National Elevation Dataset.
The data archived and distributed at EROS has countless scientific uses. For example, EROS specializes in managing and distributing earth science information that scientists use to study natural hazards. The satellite data help emergency managers decide how to handle natural hazards.
Landsat 5 captured an image of Missouri River flooding occurring along the Iowa/Nebraska border on August 1, 2011. A before and after comparison clearly shows the extent of the inundated lands.
Image: The Landsat 7 image from May 18, 2010, shows the area before the flood. The Landsat 5 image from August 1, 2011, shows the extent of the flood.
Studying the effects of fire
Satellite imagery is extensively used to measure the extent of wildfires and monitor vegetation recovery after a fire. These Landsat images reveal the extent of a 2011 fire in south central Texas.
Image: These Landsat 5 images were acquired before (August 26, 2011) and after (September 11, 2011) a wildfire in Texas.
This ASTER image shows a vigorous volcanic plume streaming northeast from the summit of Kizimen volcano, on Russia’s Kamchatka Peninsula. The white part of the plume is likely rich with steam, while the tan plume is primarily ash. Several dark streaks lie to the south of the summit—probably traces of pyroclastic flows.
Image: This ASTER image of Kizimen volcano was acquired February 25, 2011.
Besides natural changes to the land, satellite images can be used to monitor how people change the land, such as rain forest deforestation. These images in Rondônia, Brazil, show not only the deforestation but also a new reservoir behind a hydroelectric dam.
Image: Extensive rain forest deforestation is revealed in these Landsat 5 images from June 24, 1984, and August 6, 2011.
Studying urban growth
Tracking urban expansion helps city planners manage future growth. Images acquired over the Twin Cities of Minneapolis and St. Paul, Minnesota, illustrate the expansion of the population centers in a major economic region of the Upper Midwest.
Image: These Landsat 5 images show the growth of Minneapolis and St. Paul, Minnesota, from July 25, 1988, to July 25, 2011.
Studying land use
Agricultural practices differ around the world, but all are examples of a type of land use that changes the landscape. This montage of ASTER images illustrates six distinct agricultural practices.
Image: ASTER images from upper left to lower right depict agriculture in Minnesota; Kansas; northwest Germany; Santa Cruz, Bolivia; Bangkok Thailand; and southern Brazil.
The United Nations Environment Programme (UNEP) at EROS
The United Nations Environment Programme (UNEP) located its North American Global Resource Information Database (GRID) office at EROS in 1991. Designated as GRID-Sioux Falls, the office functions as a partnership between UNEP, USGS, and NASA. GRID-Sioux Falls makes environmental data available to developing countries and frequently is host to scientists from these countries. The extensive archive of satellite images and other data housed at EROS helps enhance the scientific basis for decision making and advance sustainable development initiatives.
Image: The UNEP-GRID office at EROS allows us to help scientists in countries worldwide use the archive.
The globe in the EROS lobby
The EROS lobby features a 6-foot-tall rotating globe. One inch on this globe represents about 100 miles. This globe gives us some perspective on distances in space. For example, on this scale, the International Space Station orbits Earth about 2.5 inches from the surface. And the Moon would be about 200 feet away.
For some further perspective, Earth-observing satellites monitor the Earth’s landmasses and coastal areas. But land only covers about 30% of the entire surface area of our planet. And much of that land area is uninhabitable because it’s desert, tundra, or ice caps. Overall, only 6% of Earth is habitable. This emphasizes the importance of monitoring the Earth with satellites to see how remote areas are changing and how the places we live are changing.
Image: One inch on the 6-foot-tall rotating globe represents about 100 miles.
The Don Lee Kulow Library at EROS
The Don Lee Kulow Memorial Library is a technical reference source for EROS scientists, students, engineers, and professional staff to help perform their work and keep up to date in their disciplines. The library also is a source of information on land remote sensing and global environmental change for people around the world.
Image: Staff at EROS has access to print and audiovisual collections housed within the EROS library, digital reference and research literature, and materials from libraries worldwide.