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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LiDAR point cloud from the Yellowscan VX20 scanner of the Downing Reservoir on the Denver Federal Center
USGS elevation data available through The National Map was converted to Cloud Optimized Geotiff (COG - GeoTIFF) format in mid-December, 2019. This change was made to improve product processing time, storage, and to support new and evolving cloud processing capabilities.  GeoTIFF is a widely supported raster format and is directly useable by most...
Cloud Hosting Solutions
Landsat data continue to be freely available through traditional USGS tools such as EarthExplorer, but if you prefer to access the data in the cloud, an Amazon Web Services (AWS) account is required.  Landsat data are available in the cloud via the AWS Oregon us-west-2 region. There is no charge for the Landsat data, but charges from the cloud...
Landsat 8 image of Maui before fire
Yes. Regardless of how it is accessed, Landsat data are controlled by the USGS and considered to be an official USGS record in the public domain. Permission is not required for use. We do request that you acknowledge the USGS as the source.  Learn More:   USGS Copyrights and Credits statement  Landsat Commercial Cloud Data Access 
Example of the Landsat 8 Aquatic Reflectance Science Product
Some Landsat products include Quality Assessment (QA) bands with unsigned integers that represent bit-packed information for each pixel. Details for individual products are at:  Landsat Level-1 (Collection 1 and Collection2)  Landsat Level-2 Surface Reflectance    Landsat Level-2 Provisional Aquatic Reflectance   These files must be unpacked to a...
Front page of USGS topographic maps symbol sheet
Like topographic maps, topographic map symbols have evolved over time. There is no single document that describes all the symbols used on all USGS topographic maps.   Topographic Map Symbols – Covers symbols on maps published 1947-2009. Most of these symbols are still in use. US Topo maps published 2013-present (PDF format only) have a topographic...
Image of 1:50,000 scale NGA Christmas, AZ topo map
The USGS has a limited number of 1:50,000-scale maps available for the United States. These are maps that the National Geospatial Agency (NGA) has released for sale to the public.   To see which maps are available for sale (or free digital download), go to the online USGS Store:  Click on “Maps” in the left navigation menu. Look for the NGA...
Example of Landsat Collection 2 Surface Reflectance
Landsat Collection 2 marks the second major reprocessing event of the USGS Landsat archive. Continuing the tiered collection management structure implemented in Landsat Collection 1, Landsat Collection 2 introduces several advancements in data processing, algorithm development, as well as data access and distribution capabilities, including:  ...
Landsat Collection 2 Sample Data Example
The naming convention for Landsat Collection 2 Level-1 products remains the same as in Collection 1.   While most of Landsat Collection 2 scenes are produced to both Surface Reflectance (SR) and Surface Temperature (ST), a small number of scenes cannot be processed to ST due to missing auxiliary data. The naming convention of Landsat Collection 2...
Example of the Landsat Burned Area Science Product
Landsat Collection 1 data will continue processing until at least one year after the public release of Collection 2 to allow the user community enough transition time to the new Collection 2 data.  Collection 1 U.S. Landsat ARD (Analysis Ready Data) and Collection 1 Landsat Level-3 science products (Burned Area, Dynamic Surface Water Extent, and...
Landsat Collection 2 Level-1 and Level-2 examples
Landsat Collection 2 Level-2 Surface Reflectance and Surface Temperature products are scene-based, are produced within the standard processing system, and are made available to download directly from EarthExplorer. In comparison, Landsat Collection 1 Level-2 products are only available via on-demand processing (Surface Reflectance, scene-based),...
Landsat Collection 2 Generation Timeline
Landsat Level-2 Surface Reflectance and Surface Temperature products require Landsat Collection 2 Level-1 scenes that have been processed to Tier 1 or Tier 2, as well as additional auxiliary data. For Landsat 7, the timeframe from acquisition (Real-Time (RT)) to Tier 1 or Tier 2 takes approximately 25-27 days. For Landsat 8 scenes, the timeframe...
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...