Frequently Asked Questions

Mapping, Remote Sensing, and Geospatial Data

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

Filter Total Items: 354
Earth as Art - Landsat 8
Ascending (nighttime) WRS-2 Path/Row numbers are different from descending (daytime) Path/Rows. Cloud cover values for Landsat night scenes will always be zero. If you know the daytime path/row or coordinates and want to know the nighttime path/row, use the WRS-2 Path/Row to Latitude/Longitude Converter. Use EarthExplorer to search using path/row...
Satellite image showing a picture of northeastern Alaska.
The Landsat Collection 1 Level-1 product identifier includes the Collection processing levels, processing date, collection number, and collection iter category: LXSS_LLLL_PPPRRR_YYYYMMDD_yyyymmdd_CC_TX Where: L = Landsat X = Sensor (“C”=OLI/TIRS combined, “O”=OLI-only, “T”=TIRS-only, “E”=ETM+, “T”=“TM, “M”=MSS) SS = Satellite (”07”=Landsat 7, “08...
Landsat 7 ETM+ Surface Reflectance
Landsat Collection 1 Level-1 data are not corrected for atmospheric conditions, however Landsat Science Products, which include Level-2 Surface Reflectance and Provisional Surface Temperature, and Level-3 Burned Area, Dynamic Surface Water Extent, and Fractional Snow Covered Area are atmospherically corrected. Learn more: Landsat Collections...
Landsat 7 Enhanced Thematic Mapper Plus (ETM+) Level-1 Data
The table below shows the Landsat Collections Level-1 processing levels: Landsat Level-1 Processing Levels Processing Level Description Terrain Precision Correction (L1TP) Radiometrically calibrated and orthorectified using ground control points (GCPs) and digital elevation model (DEM) data to correct for relief displacement.The highest...
Example visualization of U.S. Landsat Analysis Ready Data tile-based structure and time-series stacking.
U.S. Landsat Analysis Ready Data (ARD) are pre-packaged and pre-processed bundles of Landsat data products that make the Landsat archive more accessible and easier to analyze, and reduce the amount of time users spend on data processing for time-series analysis. ARD contains Level-2 products derived from Landsat Collections Level-1 scenes. ARD are...
Landsat 9 logo
Landsat 9 will carry the same instruments that are on the Landsat 8 satellite but with some improvements: Operational Land Imager-2 (OLI-2) for reflective band data. Thermal Infrared Sensor-2 (TIRS-2) for the thermal infrared bands. OLI-2 will have a slightly improved signal-to-noise ratio over Landsat 8's OLI. Landsat 9’s TIRS-2 is a Class...
Rendering of Landsat 9
Landsat 9—a partnership between the USGS and NASA—has a launch readiness date of December 2020. Landsat 9 will be launched from Space Launch Complex 3E at Vandenberg Air Force Base in California and will be delivered into orbit by a United Launch Alliance Atlas V 401 launch vehicle. Learn more: Landsat 9 Mission Since 1972, Landsat satellites...
Scanned USGS historical map of the Yorktown, Virginia area, circa 1907
The primary purpose of the Historical Topographic Map Collection (HTMC) project is to keep older USGS topographic quadrangle maps -- those published between 1884 and 2006 -- available to the public. This is fundamentally a document preservation project. These maps are part of the U.S. public record, and have many uses for historic analysis, but...
Historical USGS topographic map of the Prescott, Arizona area
This question has many variations. The following comments, from actual customer mail, are all about the same issue: Older topo maps seem to have a neatline that doesn’t quite align geographically with the quad boundaries of topos post-2000. Our [independent] coordinates, plotted on the USGS Topographic Map using the geospatial tool, have a...
Screen shot of National Map Advanced Viewer
USGS online maps (for example, The National Map Viewer) present several background map views. Unlike similar commercial applications, these USGS maps use public domain data. Connecting to services is the preferred method of using these base map displays, but some users want to host their own copies of the underlying data. Following is an...
LiDAR image of a river
Amazon Web Services (AWS) provide an import/export capability that allows data residing in Amazon to be transferred to physical storage devices for a fee. If you want to send your own hard drive to Amazon and you need 16 TB or less transferred, the Import/Export Disk option is recommended by Amazon. Pricing can be viewed at https://aws.amazon.com/...
Lidar image of Pittsburgh
The USGS lidar data is available from an Amazon S3 Requester Pays bucket named usgs-lidar.  The data is arranged by projects and is only available in LAZ format: Bucket Name: usgs-lidarBucket Region: US West (Oregon) To access the usgs-lidar bucket a user must create an Amazon AWS account at https://aws.amazon.com/free/ so that any charges...