Frequently Asked Questions
Mapping, Remote Sensing, and Geospatial Data
The USGS provides the mapping and digital geospatial foundation for the Nation.
The USGS does not require a specific format when citing our datasets, but a few suggestions and examples are below.
Citation for Datasets
Author: U.S. Geological Survey
Release date: the first four numbers of <pubdate> from dataset metadata for the year of the release date. For example, if the <pubdate> is 20190426, the year 2019...
Where can I find a 3D Elevation Program (3DEP) DEM status map and get information on recent updates?
Status maps showing 3DEP product availability and recent updates can be found on the 3DEP Product Availability web page.
Areas containing recent updates are refreshed on a monthly basis. Spatial metadata shapefiles showing the updated areas for each product are also available for download from the 3DEP Product Metadata web page.
Product updates...
Digital elevation data are available 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.
The 3D Elevation Program (3DEP) products and services available through The National Map consist of standard digital elevation models (DEMs) at various...
Download all dates and scales of USGS topographic maps (both current US Topo maps and Historical topographic maps) free of charge from the following applications. With the exception of GNIS, each site has an option for toggling on map indices showing an outline of all the maps, though you might need to zoom in to see the outlines:
Map Locator on...
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
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 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...
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...
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...
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...
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 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...