Landsat Collection 2: What Changed in the USGS Landsat Archive

Landsat Collection 2 reprocessed the U.S. Geological Survey's Landsat archive using newer methods for processing, algorithms, access and distribution.

• Level-1 data from all sensors since 1972 (and Landsat 9, once launched).
• Level-2 global surface reflectance and surface temperature products for data since 1982, beginning with the Thematic Mapper (TM).

A Landsat 5 scene three ways: Level-1 top of atmosphere (left), and Level-2 surface reflectance (center) and surface temperature in kelvin (right). USGS.

The main improvements

Better geometric accuracy

The Ground Control Points of Landsat 8's Operational Land Imager (OLI) were re-based on the Global Reference Image of the European Space Agency's Copernicus Sentinel-2. That makes the whole Landsat archive line up better, in space and time, with Europe's Sentinel-2 missions.

New elevation models

Collection 2 uses 3-arc-second (90-meter) elevation sources:

• Canadian Digital Elevation Model (updated)
• Global Land Survey DEM
• Greenland Mapping Project (GIMP) DEM
• NASADEM — NASA's Shuttle Radar Topography Mission, reprocessed
• National Elevation Dataset for Alaska (new)
• Norwegian Polar Institute elevation data
• Sweden, Norway and Finland national elevation data
• ArcticDEM, derived from WorldView

Which elevation model covers where. USGS.

Better calibration

Several radiometric calibration improvements were made for Landsat 5 TM and Landsat 8 data — including a fix for striping in the Thermal Infrared Sensor (TIRS).

Landsat 8 TIRS Band 10, processed in Collection 1 (left, with striping) and Collection 2 (right). USGS.

Quality bands

• Level-1 data come with a Pixel Quality Assessment Band and a Radiometric Saturation and Quality Assessment Band.
• Level-2 products add, alongside the Level-1 bands: a surface reflectance aerosol band for Landsat 8, a surface reflectance cloud band for Landsat 4–7, and a surface temperature quality band — so quality information is consistent across products.

Metadata

Collection 2 adds an XML file to the MTL metadata file, making the inventory more consistent, easier to script machine-to-machine, and faster to query. Some metadata fields shown on EarthExplorer changed too.

Cloud-ready files

Data come as Cloud Optimized GeoTIFFs (COGs) — an extension of the GeoTIFF format that lets users fetch a whole product bundle (all bands) or just the bands they need from the cloud.

Tiers and timing

Collection 2 keeps the tiered Level-1 inventory. The tiers:

• keep processing consistent and traceable, with known data quality;
• supply Real-Time (RT) data within 12 hours of acquisition for the International Charter, to help lessen the effects of disasters on life and property;
• hold the highest-quality Landsat Level-1 data ever made;
• support stacking data and time-series analysis pixel by pixel.

Typical Collection 2 production timeline for Landsat 7–9. USGS.

Level-2 products use NASA's GEOS-5 FP-IT atmospheric data (Goddard Earth Observing System Model, Version 5, Forward Processing for Instrument Teams); Landsat 9 will too.

Getting the data

• Free: download from the USGS EarthExplorer. The Landsat no-cost, open-access policy, in place since 2008, continues.
• In the cloud: Collection 2 is also available through commercial cloud access. Users who run their own algorithms there may pay fees.

More: Landsat Collection 2 on the USGS Landsat Missions website.

Sources

Based on Landsat Collection 2, USGS Fact Sheet 2021–3002 (version 1.1, January 15, 2021), U.S. Geological Survey; a work of the United States government in the public domain. The four figures are taken from the fact sheet's PDF, which the import had left out. The source's "Operational Landsat Imager" is the Operational Land Imager, as its own figure note says.