Landsat Missions

Web-Enabled Landsat Data (WELD)

The Web-enabled Landsat Data (WELD) project is funded by the National Aeronautics and Space Administration (NASA) Making Earth System Data Records for Use in Research Environments (MEaSUREs) program under Cooperative Agreement NNX08AL93A. 

WELD produced large area 30-meter composited mosaics from Landsat terrain corrected (Level-1T) data. Both projects are funded by NASA's Making Earth System Data Records for Use in Research Environments program with significant USGS cost sharing.

The WELD data products are processed so users do not need to apply the equations, spectral calibration coefficients, and solar information, needed to convert Landsat digital numbers to reflectance and brightness temperature. They are defined in the same coordinate system and align precisely, making them simple to use for multi-temporal applications. The products provide consistent data that can be used to derive higher-level land cover as well as geo-physical and biophysical products for assessment of surface dynamics and to study Earth system functioning.

CONUS and Alaska WELD
Weekly, monthly, seasonal and annual 30-meter continental U.S. (CONUS) and Alaska composites generated from Landsat 7 ETM+ data are available for 10 years (2003-2012).  Products are available in Geographic Tagged Image File Format (GeoTIFF) through an interactive Web interface, or as Hierarchical Data Format (HDF) tiles from a direct download site.

Landsat Web Enabled Data 2007-08 Seasons Example

This animation displays the visible changes in seasons using Landsat Web Enabled Data (WELD) image mosaics.  Courtesy of South Dakota State University.