Frequently Asked Questions

Mapping, Remote Sensing, and Geospatial Data

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

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Example of Landsat Collection 2
The fill values and scale factors of Landsat Collection 2 Level-2 products were updated to be consistent with that of Landsat Collection 2 Level-1 data, while using the unsigned integer data type more efficiently.  As shown in the table below, the fill value of the Surface Reflectance and Surface Temperature bands were changed from “-9999” in...
Landsat Collection 2 product examples
Search Landsat Collection 2 Level-1 and Level-2 products using EarthExplorer, which is the primary portal used to search all data held in the USGS EROS archives.   While Landsat Collection 2 products are processed and stored in the USGS Cloud Hosting Solution (CHS) environment, downloads are managed through EarthExplorer. The USGS Landsat no-cost...
Color Landsat 8 image of Palm Springs, CA
A Cloud Optimized GeoTIFF (COG) is a GeoTIFF file with an internal organization that enables more efficient workflows in the cloud environment.  It does this by leveraging the ability of clients issuing ​HTTP GET range requests to ask for just the parts of a file they need. Learn more:   Landsat COG Data Format Control Book   USGS Digital...
L8 Collection 2 Full Resolution Browse Samples: Reflective, Thermal, and Quality Band
Similar to Landsat Collection 1 LandsatLook Images, the Landsat Collection 2 Full Resolution Browse Images are .JPG and .TIF images with geographic referencing that are compressed and stretched to create an image optimized for image selection and visual interpretation. They are derived from Landsat Collection 2 Level-1 data and are available to...
National Map Viewer with draw tool open
Base map data layers in The National Map Viewer are for viewing only. This application is designed for visualizing data, combining different data layers, and creating (and printing) your own maps. To download data from The National Map, see the link at the top of the Viewer for the Data Downloader.  None of the base map layers in the Viewer are ...
Global Multi-resolution Terrain Elevation Data 2010 (GMTED2010)
Download free global elevation data products using AppEEARS or  EarthExplorer. Free registration is required. In AppEEARS: Download Aster Global Digital Elevation Model (GDEM version 3) 1-arc-second (30m) resolution GeoTIFF format Acquired 2000-2013   In EarthExplorer, select “Digital Elevation” under the "Data Sets" tab and choose an option: ...
Color map of land use and land cover in West Africa, circa 1975
Access global land cover data using two sources on EarthExplorer: Global Land Cover Characterization (GLCC)  Select "Land Cover" under the "Data Sets" tab in EarthExplorer. Then select area of coverage and projection under "Additional Criteria" tab. Derived from 1-km Advanced Very High Resolution Radiometer (AVHRR) data collected April 1992-March...
Screenshot from NHD Seminar 6 Presentation showing Terrain Catchments
The USGS does not require a specific format when citing data obtained through The National Map; you should follow the citation guidelines provided by instructors or publication editors as appropriate. The following should help you find the information that you need:  Citation for Datasets Author: U.S. Geological Survey Release date: the first...
Map of Fiscal Year 2020 status of 3D Elevation Program (3DEP) quality data, as of September 2020
3D Elevation Program (3DEP) product updates and status maps are available at these sites: 3DEP Product Availability 3DEP Data Acquisition Status Maps Acquire updated products through The National Map Downloader, The National Map Services, or through a bulk data request. 3D Elevation Program News The National Map Data Delivery News  Subscribe to...
Lidar-derived Digital Elevation Model over Zion National Park, Utah
Digital elevation data for the United States and its territories are available through The National Map Downloader. Click the “Help” link at the top of the page for detailed instructions on how to find and download data. There is a separate site for The National Map Services. The 3D Elevation Program (3DEP) products and services available through...
1951 USGS legacy topographic map of the Monson West, ME
The U.S. Geological Survey (USGS) has been the primary civilian mapping agency of the United States since 1879. The best known USGS maps are the 1:24,000-scale topographic maps, also known as 7.5-minute quadrangles. Download all dates and scales of USGS topographic maps free of charge from the following applications or order paper copies of all...
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