New Paper Promotes the 50-year Landsat Collection 2 Archive
Recognizing the need for consistently processed remotely sensed data, the USGS initiated collections-based processing to ensure superior radiometric and geometric quality through time and across all Landsat instruments. In 2016, the entire Level-1 data archive were processed as Collection 1. In preparation for Landsat 9, the USGS archive was reprocessed as Collection 2 in 2020.
USGS Research Physical Scientist Dr. Chris Crawford led the efforts to document the rationale, the contents and advancements provided by Landsat Collection 2, and highlight the differences between the Collection 1 and Collection 2 products.
The paper, which concludes with discussion of likely improvements expected in Collection 3 in preparation for the Landsat Next mission that is planned for launch in the early 2030s, can be accessed at https://doi.org/10.1016/j.srs.2023.100103.
Landsat Collection 2 is composed of over 11 million Level-1 images of data collected by the Landsat 1–5 Multispectral Scanner (MSS), Landsat 4 and 5 Thematic Mapper (TM), Landsat 7 Enhanced Thematic Mapper Plus (ETM+), and Landsat 8 and 9 Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS) sensors. Collection 2 products include calibrated and geolocated Level-1 top of atmosphere (TOA) heritage images defined in the Universal Transverse Mercator (UTM) projection; Level-2 surface reflectance and surface temperature images; and for select U.S. regions, Analysis Ready Data (ARD) gridded tiled products defined in the Albers equal area projection. The Collection 2 Level 2 products and U.S. ARD were certified by the Committee on Earth Observation Satellites (CEOS) as being analysis ready data compliant (processed to a minimum set of requirements and organized into a form that allows for analysis with minimal additional user effort that facilitates interoperability with other Earth observation datasets).
Landsat Collection 2 processing implemented the following data improvements:
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Improved geometric accuracy of the data with updated and new ground control points
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Improved elevation modeling with additional and new digital elevation sources
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Global Level-2 Science and Atmospheric Auxiliary Products
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A correction for the Landsat 8-9 TIRS striping effect
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Consistent Quality Assessment Bands
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Updated and Consistent Metadata Files
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Cloud Optimized File Format
With the release of Landsat Collection 2, the USGS implemented a commercial cloud computing architecture to efficiently process the archive and enable direct cloud access of the Landsat products. To learn more, visit the USGS Landsat Collection 2 webpage.