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Full catalog/GWELDYR
GWELDYR·v003·dataset

Yearly cloud-free Landsat land mosaic (30 m)

NASA Global Web-Enabled Landsat Data Annual Global 30 m V003
land NASA LPCLOUD Level 2 HDF4
In plain English

What it measures. Yearly, cleaned-up mosaics of the land surface at 30-meter resolution, combining the clearest available Landsat views. It includes surface reflectance bands, an estimate of how warm surfaces look in the thermal band, and a greenness index (NDVI) that tracks vegetation.

How it's made. Assembled from all available Landsat 4, 5, and 7 imagery, adjusted for viewing-angle effects and stitched into consistent annual layers on a standard map grid.

How & where you'd use it. Gives researchers a clean, ready-to-use yearly snapshot for mapping land cover and tracking how landscapes and vegetation change over time.

What's measured

LAND SURFACE › SURFACE RADIATIVE PROPERTIES › REFLECTANCE

Coverage & cadence

  • Time span2009-01-01 → 2011-12-31
  • Measured byLANDSAT-7 (ETM+) · LANDSAT-5 (TM)
  • Processing levelLevel 2
  • Spatial extent-180, -90, 180, 90
  • FormatsHDF4
  • StatusCOMPLETE

What you can do with it

  • Track deforestation, fire scars and land-cover change
  • Monitor crop and vegetation health (NDVI/EVI)
  • Map how built-up vs. green an area is over time
Official description

The NASA Making Earth System Data Records for Use in Research Environments ([MEaSUREs](https://earthdata.nasa.gov/about/competitive-programs/measures)) Global Web-Enabled Landsat Data Annual (GWELDYR) Version 3 data product provides Landsat data at 30 meter (m) resolution for terrestrial non-Antarctica locations over annual reporting periods for the 2010 epoch. GWELD data products are generated from all available Landsat 4 and 5 Thematic Mapper (TM) and Landsat 7 Enhanced Thematic Mapper Plus (ETM+) data in the U.S. Geological Survey (USGS) Landsat archive. The GWELD suite of products provide consistent data to derive land cover as well as geophysical and biophysical information for regional assessment of land surface dynamics. The GWELD products include Nadir Bidirectional Reflectance Distribution Function (BRDF)-Adjusted Reflectance (NBAR) for the reflective wavelength bands and to top of atmosphere (TOA) brightness temperature for the thermal bands. The products are defined in the Sinusoidal coordinate system to promote continuity of NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) land tile grid Provided in the GWELDYR product are layers for surface reflectance bands 1 through 5 and 7, TOA brightness temperature for thermal bands, Normalized Difference Vegetation Index (NDVI), day of year, ancillary angle, and data quality information. A low-resolution red, green, blue (RGB) browse image of bands 5, 4, 3 is also available for each granule. Known Issues * GWELDYR known issues can be found in Section 4 of the Algorithm Theoretical Basis Document (ATBD). Please note that the version 3.0 GWELD products for 2009, 2010 and 2011 are defined in HDF4 which cannot be read correctly by GDAL/ArcGIS. This is not an issue for the version 3.1 GWELD products

Get the data

gweldyr_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="GWELDYR",
    version="003",
    bounding_box=(-122.5, 37.2, -121.8, 37.9),  # your area (W,S,E,N)
    temporal=("2024-01-01", "2024-12-31"),       # your dates
)
files = earthaccess.open(results)   # stream straight from LPCLOUD
Browsing CMR needs no login. Downloading or streaming bytes needs a free Earthdata Login + the earthaccess package.