Frequently Asked Questions

Mapping, Remote Sensing, and Geospatial Data

The USGS provides the mapping and digital geospatial foundation for the Nation.

Filter Total Items: 372
NGTOC - 3DEP mountains
Download free digital elevation data through The National Map Download Client. Click the “How To” link at the top of the viewer for detailed instructions on how to find and download data; see The National Map training videos for step-by-step demonstrations. Download standard elevation products (Digital Elevation Models, or DEMs) in these...
1951 USGS legacy topographic map of the Monson West, ME
USGS topographic maps (both current US Topo maps and Historical topographic maps) can be downloaded free of charge from these applications. With the exception of GNIS, each application has an option for toggling on map indices showing an outline of all the maps: The Map Locator on the USGS Store -- Search and download digital maps in PDF format...
Sentinel-2A satellite image showing the Crater Lake in Oregon.
The Sentinel-2A MultiSpectral Instrument (MSI) data has spectral bands very similar to Landsat 8 (excluding the thermal bands of Landsat 8’s Thermal Infrared Sensor). Source: https://landsat.gsfc.nasa.gov/wp-content/uploads/2015/06/Landsat.v.Sentinel-2.png (Public domain.)   Learn more: USGS EROS Sentinel-2 Landsat Comparison
UTM Grid conterminous 48 United States
Traditional Universal Transverse Mercator (UTM) convention distinguishes between the Northern and Southern Hemispheres. In the Northern Hemisphere, the UTM zone is a positive value or identified as UTM North. In the Southern Hemisphere, the UTM zone is a negative value or identified as UTM South. UTM North scenes in this convention have a false...
Landsat image of sediment deposited into the Gulf of Mexico
Landsat data products held in the USGS archives can be searched and downloaded at no charge from a variety of sources. Visit the Landsat Data Access web page for information about how Landsat data products can be downloaded individually or in bulk. Landsat imagery not found in the USGS archive might have been collected by one of the USGS...
Square satellie image that is mostly grey with small blobs and wisps of white clouds
Landsat 8's Band 9 1.360-1.390 µm detects thin, high-altitude clouds composed of ice crystals that might not be visible in other spectral bands. In Band 9, cirrus clouds appear bright while most land surfaces appear dark through an otherwise cloud-free atmosphere containing water vapor. Learn more: Landsat 8 Mission Landsat 8 bands (NASA) Landsat...
Algal bloom off the coast of Brazil, Landsat 2017 image
Landsat 8’s Band 1 (0.433-0.453 µm) is useful for imaging shallow water and tracking fine atmospheric particles like dust and smoke. Since water absorbs and scatters light, oceans and lakes tend to look dark or lack detail on satellite images, especially in the sediment-laden waters near coastlines. Band 1 reflects blues and violets and displays...
Earth As Art image of the Beni River in Bolivia
The first indication you have data processed meeting Collections specifications is that your data will have a Landsat Product Identifier, not the historical Landsat Scene ID. Along with information inherited from the Scene ID, the Landsat Product Identifier includes the processing level, processing date, collection number, and collection category...
Canyonlands National Park as seen by Landsat 8
The file sizes of Landsat Collection 1 Level-1 data products are listed in the table below. Sensor Compressedfile Uncompressedfile Landsat 8 OLI/TIRS 919 MB 1.61 GB Landsat 7 ETM+ 235 MB 785 MB Landsat 4-5 TM 150 MB 500 MB Landsat 1-5 MSS 20 MB 75 MB  
Landsat image of flooding along Missouri River from March 2019
Landsat Collections Real-Time (RT) data provide temporary data within 12 hours of acquisition in support of the International Charter to help mitigate the effects of disasters on human life and property. The RT tier contains data received from Landsat 8 and Landsat 7 immediately after acquisition. Estimated radiometric and geometric calibration...
Landsat 8 image
Landsat Collection Tiers are the inventory structure for Level-1 data products and are based on data quality and level of processing. The tier definition purpose is to support easier identification of suitable scenes for time-series pixel-level analysis, and provide temporary data that are processed immediately upon downlink to be dispensed...
Landsat Collections Fact Sheet
In 2016, the USGS reorganized the Landsat archive into a tiered collection. This structure ensures that Landsat Level-1 products provide a consistent archive of known data quality to support time-series analyses and data “stacking”, while controlling continuous improvement of the archive and access to all data as they are acquired. Learn more:...