Frequently Asked Questions

Mapping, Remote Sensing, and Geospatial Data

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

Filter Total Items: 233
World Reference System-2 (WRS-2) - Day/Descending
The Worldwide Reference System (WRS) is a global system that catalogs Landsat data by Path and Row numbers. Landsat satellites 1, 2 and 3 followed WRS-1, and Landsat satellites 4,5,7, and 8 follow WRS-2. Learn more: Landsat Path Row Shapefiles and KML Files The Worldwide Reference System (NASA)
Landsat Level-2 Surface Reflectance Example
There are several Landsat data products that are useful for science applications and land use/land change studies: Landsat Collections Level 1 - Ensures that the data in the Landsat Level-1 archive are consistent in processing and data quality to support time-series analyses and data stacking. Each Level-1 data product includes individual spectral...
Geometric Desert - Earth As Art image of Egypt
Definitive Ephemeris is used for geometrically correcting Landsat 7 data and providing improved accuracy over predicted ephemeris. Learn more (and download DE files): Landsat Definitive Ephemeris
Aug 2013 Response Linearization Look Up Tables Update Close up - Band 6
Landsat Response Linearization Look Up Tables (RLUT) are additional files that accompany Calibration Parameter Files (CPFs) and contain a mapping lookup table to linearize the output of the Landsat 8 Operational Land Imager (OLI) detectors. Learn more (and download RLUT files): Landsat Response Linearization Look Up Tables
White Sands Radiometric Calibration Site
Landsat Bias Parameter Files (BPFs) supply radiometric correction parameters that are applied during Level-1 processing of Landsat data. Learn more (and search for BPF files): Landsat Bias Parameter 
Calibration/Validation Test Sites
Landsat Calibration Parameter Files (CPFs) provide radiometric and geometric coefficients needed for processing of raw, uncorrected Landsat image data into Level-1 data products. Over 15,000 coefficients are issued to span distinct timeframes and are updated with improved calibration coefficients. CPFs are often updated with improved coefficients...
Landsat 8 Collection 1 Quality Assessment Example
The C Function of Mask (CFMask) algorithm populates cloud, cloud confidence, cloud shadow, and snow/ice pixels in the processing of Landsat Collections Level-1 data products, with the results represented as bit-mapped values within the Landsat Collection 1 Level-1 Quality Assessment (QA) Band.  CFMask derives from the Function of Mask (FMask), an...
Landsat 7 100,000th orbit image
The Landsat Collection 1 Level-1 product metadata (MTL.txt) file includes a SATURATION_BAND_ x”parameter for each Landsat band. This field indicates the presence of radiometric saturation for each bandin every Landsat scene. Learn more: Landsat Collections Level-1 Saturation Bits Parameter 
Zenith and Azimuth Angles Associated with Solar Angle Bands
The Landsat Collection 1 Angle Coefficient file provides sensor viewing angle model coefficients that can be used to create angle bands, and allows users to compute the solar and sensor viewing angles on a per-pixel basis. Learn more: Solar Illumination and Sensor Viewing Angle Coefficient Files 
Crop of Landsat 7 Path 38 Row 31, Acquired March 29, 2013
The Landsat 7 SLC-off artifact does not change how the data are placed into Landsat Collection tiers, as tier classifications are determined by the radiometric and geometric accuracy of each scene. Learn more: Landsat Collections Landsat Data Access
Lenticular clouds over hills in New Zealand.
Landsat Level-1 data can be rescaled to the top of atmosphere (TOA) reflectance and/or radiance using radiometric rescaling coefficients provided in the metadata file (MTL.txt) that is delivered with the Landsat Level-1 product. The MTL file also contains the thermal constants needed to convert thermal band data to TOA brightness temperature (BT...
Earth As Art image of Kazakhstan
The historical Landsat Level-1 Scene ID is in the EarthExplorer metadata. After entering a search using the historical Scene ID, the Landsat Level-1 Collection 1 Product Identifier will be returned in the search results. The results can be exported from EarthExplorer in a variety of formats for metadata parsing. We also encourage use of the Bulk...