Landsat Collections

Landsat Collection 2

Landsat Collection 2 Level-1 and Level-2 surface reflectance and surface temperature scene-based products are available to download. Tile-based Collection 2 U.S. Analysis Ready Data (ARD) will become available mid-2021. 

Level-1

Level-1

Technical information for Collection 2 Level-1 data.

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Level-2

Level-2

Technical information for Collection 2 Level-2 science products. 

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U.S. Analysis Ready Data

U.S. Analysis Ready Data

Technical information for Landsat Collection 2 U.S. Analysis Ready Data (ARD)

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CEOS CARD4L Compliance Stamp Logo

The USGS are the first recipients of the Committee on Earth Observation Satellites (CEOS) endorsement for Analysis Ready Data for Land (CARD4L)-compliant products for Landsat Collection 2 Level-2 products. This internationally recognized certification ensures that Landsat Collection 2 Level-2 products are more interoperable with other Earth observing platforms, such as Europe’s Sentinel-2 satellite, as they too work towards CARD4L-compliant products. 

(Used with permission by CEOS.)

Access Landsat Collection 1 Information

Landsat Collection 2 marks the second major reprocessing effort on the Landsat archive by the USGS that results in several data product improvements that harness recent advancements in data processing, algorithm development, and data access and distribution capabilities.

A primary characteristic of Collection 2 is the substantial improvement in the absolute geolocation accuracy of the global ground reference dataset - which improves interoperability of the Landsat archive through time. Collection 2 also includes updated global digital elevation modeling sources and calibration and validation updates.

Collection 2 includes Landsat Level-1 data for all sensors since 1972, as well as global Level-2 surface reflectance and surface temperature scene-based products from 1982 to present (excluding Landsat 1-5 Multispectral Scanner (MSS)) within defined constraints.

PLEASE NOTELandsat Collection 1 based forward processing will remain in effect through December 31, 2021, concurrent with Landsat Collection 2 based forward processing. Starting January 1, 2022, all new Landsat acquisitions will be processed into the Collection 2 inventory structure only. 

Users are encouraged to migrate their workflow to Landsat Collection 2 at their earliest convenience. Due to advancements in data processing and algorithm development, users are discouraged from using Collection 1 and Collection 2 interchangeably within the same workflow.

Collection 1 products will remain available for search and download while the USGS evaluates a formal deprecation schedule.

Visit the Landsat Data Access web page to discover how to search and download all Landsat products from USGS data portals.

Collection 2 Highlights 

Below is a high-level summary of the main improvements for Collection 2. For a more detailed description of Collection 2 processing, geometric, and radiometric improvements please visit the Collection 2 Level-1 webpage or review the accompanying documentation. 

Download this Quick Reference Guide that lists the calibration, data processing, metadata, and product differences between Landsat Collection 1 Level-1, Level-2 U.S. Analysis Ready Data (ARD), and Landsat Collection 2 products. 

  • Improved Geometric Accuracy
    Re-baselining the Landsat 8 OLI Ground Control Points (GCPs) to the European Space Agency Copernicus Sentinel-2 Global Reference Image (GRI) improves the interoperability of the global Landsat archive spatially and temporally. The January 2020: Phase 4 - Collection 2 section on the Landsat Ground Control Points webpage provides more information.  A 2019 publication shows improved accuracy in ground control by deploying a triangulation method on a continent by continent basis.
     
  • Improved Digital Elevation Modeling
    Collection 2 uses the 3-arc-second digital elevation modeling (DEM) sources listed and shown on the map below.  (Please refer to the “DATA_SOURCE_ELEVATION” field in the Level-1 metadata file to determine the DEM source used in processing.)
     
    Landsat Collection 2 Digital Elevation Modeling (DEM) sources

    Digital Elevation Sources used in Landsat Collection 2 data processing. (Click to enlarge)

  • Improved Radiometric Calibration
    Collection 2 includes several radiometric calibration improvements for Landsat 5 Thematic Mapper (TM) and Landsat 8 Operational Land Imager (OLI) data, including a correction for the TIRS striping effect (See: Radiometric Accuracy Improvements).
     
  • Global Level-2 Science and Atmospheric Auxiliary Products *COMING SOON*
    NOTE: Atmospheric Auxiliary products will become available after the final data verification is complete.

    New for Collection 2 is the processing and distribution of Level-2 surface reflectance and surface temperature science products for Landsat 4-5 TM, Landsat 7 ETM+ and Landsat 8 OLI/TIRS. Level-2 products are generated from Collection 2 Level-1 inputs that meet the <76 degrees Solar Zenith Angle constraint and include the required auxiliary data inputs to generate a scientifically viable product.  (Please note that Landsat 1-5 Level-2 MSS surface reflectance products will only become available upon the maturity of an operational atmospheric compensation algorithm which satisfies the USGS Landsat program requirements.) Landsat Collection 2 Atmospheric Auxiliary Data used in the processing of Collection 2 Level-2 products are available to download for users wanting to generate custom Level-2 products using the Collection 2 surface reflectance and surface temperature algorithms. 
     
  • Consistent Quality Assessment Bands
    Collection 2 Level-1 products are delivered with a Quality Assessment Band (QA_Pixel) and a Radiometric Saturation and Terrain Occlusion Quality Assessment Band (QA_RADSAT). Collection 2 Level-2 products will include the Level-1 QA bands as well as a surface reflectance aerosol QA Band (SR_QA_AEROSOL) and a surface temperature QA Band (ST_QA) to provide consistent QA information between products. The Landsat Collection 2 Quality Assessment Bands page provides more information about the QA bands. 
    In February 2021, an issue was been discovered in the  Pixel QA ‘clear bit’ (bit 6) for Landsat 4-7 scenes over water. Please visit the Landsat Collection 2 Known Issues page for more details about this issue.
     
  • Updated and Consistent Metadata Files
    There are several enhancements and changes between Collection 1 and Collection 2 Level-1 metadata. New to Collection 2 data is the addition of an extensible markup language (XML) to the already offered Material Library File (MTL) (Object Description Language-based) format file. The metadata files facilitate consistency, machine-to-machine scripting and rapid querying of the USGS Landsat archive.  There are also changes to the metadata fields visible on EarthExplorer and its associated applications. The Landsat Collection 2 Metadata page describes changes to each and provides files displaying the changes.
     
  • Cloud Optimized File Format
    Landsat Collection 2 Level-1 data and Level-2 products are delivered in a Cloud Optimized Georeferenced (COG) Tagged Image File Format. COGs are an extension of the current GeoTIFF file format which improves access to Geospatial datasets in a cloud-based environment by allowing users to request only the bands that they need. For additional information on the COG file format please review the Landsat Cloud Optimized GeoTIFF (COG) Data Format Control Book (DFCB).

 

Collection 2 Tiers

Landsat Collection Tiers are the inventory structure for Level-1 data products and are based on data quality and level of processing. The tier definition purpose is to support easier identification of suitable scenes for time-series pixel-level analysis, and provide temporary data that are processed immediately upon downlink to be dispensed quickly in emergency response situations with limited calibration.

Real-Time (RT)

Newly-acquired Landsat 7 ETM+ and Landsat 8 OLI/TIRS data are processed upon downlink but use predicted ephemeris (Landsat 7), initial bumper mode parameters (Landsat 7), or initial TIRS line-of-sight model parameters (Landsat 8). The data is placed in the Real-Time tier and made available for download in less than 12 hours (4-6 hours typically). Once the data have been reprocessed with definitive ephemeris, updated bumper mode parameters and refined TIRS parameters, the products are transitioned to either Tier 1 or Tier 2 and removed from the Real-Time tier. The transition delay from Real-Time to Tier 1 or Tier 2 is between 14 and 26 days. Follow-on processing details are described below.

  • Landsat 7 ETM+ acquisitions are processed immediately using predicted ephemeris and initial bumper mode parameters and placed into the Real-Time tier. Shortly after initial processing (about 1 day), the data are reprocessed using definitive ephemeris, but remain in the Real-Time tier. During a period of instrument trending/characterization (about 26 days), calibration parameter adjustments finalize the geometric correction model, and the data are reprocessed and placed into either Tier 1 or Tier 2.
  • Landsat 8 TIRS data may not meet specifications for co-registration with OLI. TIRS line-of-sight model parameters are refined based on data acquired during biweekly calibration maneuvers and scenes are reprocessed within 14 to 16 days of acquisition and placed into either Tier 1 or Tier 2.

Tier 1 (T1)

Landsat scenes with the highest available data quality are placed into Tier 1 and are considered suitable for time-series analysis. Tier 1 includes Level-1 Precision and Terrain (L1TP) corrected data that have well-characterized radiometry and are inter-calibrated across the different Landsat instruments. The georegistration of Tier 1 scenes is consistent and within prescribed image-to-image tolerances of ≦ 12-meter radial root mean square error (RMSE).

Tier 2 (T2)

Landsat scenes not meeting Tier 1 criteria during processing are assigned to Tier 2. Tier 2 scenes adhere to the same radiometric standard as Tier 1 scenes, but do not meet the Tier 1 geometry specification due to less accurate orbital information (specific to older Landsat sensors), significant cloud cover, insufficient ground control, or other factors.  This includes Systematic Terrain (L1GT) and Systematic (L1GS) processed data. Users interested in Tier 2 scenes can query the RMSE and other properties to determine their application suitability.

The Tier designation (T1, T2, RT) is visible at the end of the Landsat Product Identifier, as shown in the examples below. It is also provided as an additional metadata field in EarthExplorer. Note: Historical Landsat 4-5 TM and Landsat 7 ETM+ data received from International Ground Stations supporting the Landsat Global Archive Consolidation effort are placed in either Tier 1 or Tier 2 after Collection 1 processing.

Real-Time: LE07_L1TP_037035_20210429_20210429_02_RT
Tier 1: LE07_L1TP_013024_20061106_20200913_02_T1
Tier 2: LT05_L1GS_178058_19950410_20200912_02_T2

 

Landsat Collection 2 Known Issues

The Landsat Collection 2 Known Issues page provides information about artifacts found in Landsat Collection 2 data products, and attempts to make recommendations on how users can make corrections. 

 

Data Availability, Access, and Product Generation Timeline

Visit the Landsat Data Access web page to discover how to search and download all Landsat products from USGS data portals. The USGS Landsat no-cost open access data policy remains intact since its inception in 2008.

A typical Landsat Collection 2 product generation timeline is illustrated below (click image to enlarge).

Landsat Collection 2 Generation Timeline

Typical Landsat 7-9 Collection 2 Product Generation Timeline

Landsat 7 ETM+ and Landsat 8 OLI/TIRS Real-Time scenes are available for download within 4-6 hours after acquisition. 

For Landsat 7 ETM+, the timeframe from acquisition (Real-Time) to Tier 1 or Tier 2 takes approximately 24-26 days to allow for application of the refined bumper mode parameters to Level-1 Real-Time scenes. For Landsat 8 OLI/TIRS, it takes approximately 14-16 days to process to a Tier 1 or Tier 2 product while refined TIRS instrument line of sight model parameters are applied to Real-Time scenes.

Level-2 Surface Reflectance and Surface Temperature products are typically available within 24 hours after a scene has been processed into Tier 1 or Tier 2.

Landsat 7 and Landsat 8 both utilize NASA's Goddard Earth Observing System Model Version 5 Forward Processing for Instrument Teams (GEOS-5 FP-IT) Atmospheric Assimilation Products for Level-2 product generation.

Upon nominal launch and on-orbit checkout in September 2021, Landsat 9 will deliver Collection 2 Level-1 Tier 1 or Tier 2 scenes within 4-6 hours of acquisition, and a Level-2 Surface Reflectance and Surface Temperature product within 3 days of acquisition. Landsat 9 will also utilize the GEOS-5 FP-IT atmospheric auxiliary data product for Level-2 product generation. 

 

 

Documentation 

Masek, J., M.A. Wulder, B.L. Markham, J. McCorkel, C.J. Crawford, J. Storey, and D.T. Jenstrom. (2020). Landsat 9: empowering open science and applications through continuity. Remote Sensing of Environment 248. doi:10.1016/j.rse.2020.111968 

Users are encouraged to reference the COG Data Format Control Book (DFCB) for a detailed description of the image, product and metadata files. Together with the instrument specific Level-1 DFCBs, the COG DFCB provides a comprehensive overview of the new Landsat Collection 2 products.

Landsat Cloud Optimized GeoTIFF (COG) Data Format Control Book

Collection 2 Level-1 Documents

Collection 2 Level-2 Documents

 

Summary of Enhancement and Improvements 

A summary of the enhancements and improvements between Collection 1 and Collection 2 is provided in this quick reference guide.