NASA Web-Enabled Landsat Data Alaska Latitude/Longitude

PI: David Roy

WELDAKLL.015 was decommissioned on December 2, 2019. Users are encouraged to use the improved monthly and annual Global Web-Enabled Landsat Data (GWELD) Version 3.1 (GWELDMO.031 and GWELDYR.031) datasets and the USGS U.S. Landsat Analysis Ready Data Level-2 Data Product (Landsat ARD).


The NASA Web-Enabled Landsat Data (WELD) Alaska Latitude Longitude (LL) products are defined with 30 meter (m) composite pixel of the center latitude/longitude point. The NASA WELD data contain a range of values for the minimum/maximum latitude and longitude points. The LL products were created to account for the actual center pixel latitude and longitude points.

WELD systematically generated 30 m composited Landsat Enhanced Thematic Mapper Plus (ETM+) mosaics of the United States and Alaska from 2002 to 2012 to provide consistent data for deriving land cover as well as geophysical and biophysical products for regional assessments of surface dynamics for effective study of Earth system function. WELDAKLL is distributed in Hierarchical Data Format 4 (HDF4).

The WELD project is funded by the National Aeronautics and Space Administration (NASA) and is a collaboration between the United States Geological Survey (USGS) Earth Resources Observation and Science (EROS) Center and the South Dakota State University (SDSU) Geospatial Sciences Center of Excellence (GSCE).

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Improvements/Changes from Previous Versions

Version 1.5 is the original version.

Collection and Granule


Characteristic Description
CollectionMEaSUREs WELD and GWELD
File Size~305 MB
Temporal ResolutionOther
Temporal Extent2002-12-01 to 2012-12-31
Spatial ExtentAlaska (United States)
Coordinate SystemAlbers Equal Area
DatumWorld Geodetic System (WGS84)
File FormatHDF4
Geographic Dimensions150 km x 150 km


Characteristic Description
Number of Science Dataset (SDS) Layers2
Columns/Rows5000 x 5000
Pixel Size30 m

Layers / Variables

SDS Name Description Units Data Type Fill Value No Data Value Valid Range Scale Factor
Longitude Center Longitude of each 30 m pixel Degree 64-bit floating point N/A N/A N/A N/A
Latitude Center Latitude of each 30 m pixel Degree 64-bit floating point N/A N/A N/A N/A

Product Quality

WELD Version 1.5 product quality information can be found in section 6 of the WELD ATBD.

Known Issues

WELD Version 1.5 known issues can be found on the page 21 of the WELD Version 1.5 User Guide.

About the image

NASA Web-Enabled Landsat Alaska WELD Tile system over Alaska, United States.

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User Guide
Algorithm Theoretical Basis Document (ATBD)

Using the Data

Access Data