Frequently Asked Questions
Mapping, Remote Sensing, and Geospatial Data
The USGS provides the mapping and digital geospatial foundation for the Nation.
Browse Mapping, Remote Sensing, and Geospatial Data science related to:
• US Topo
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...
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...
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...
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...
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 Download Client. None of the base map layers are available...
Download global elevation data products using EarthExplorer or AppEEARS.
In EarthExplorer, select “Digital Elevation” under the "Data Sets" tab and choose an option:
· Shuttle Radar Topography Mission (SRTM)
1-arc-second (30m) resolution
DTED, BIL, and GeoTIFF formats
Acquired 2000
· Global Multi-resolution Terrain Elevation Data 2010 (...
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.
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 1993...
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 3D Elevation Program (3DEP) product availability and recent updates are on the 3DEP Product Availability site.
Areas containing recent updates are refreshed on a monthly basis. Download spatial metadata shapefiles showing the updated areas for each product from the 3DEP Product Metadata site.
Acquire updated products through...
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. There is a seperate site for Services.
The 3D Elevation Program (3DEP) products and services available through The National Map consist of standard digital...
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...
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