Landsat Collections

Landsat Collection 1

Landsat Collection 1 consists of Level-1 data products generated from Landsat 8 Operational Land Imager (OLI)/Thermal Infrared Sensor (TIRS), Landsat 7 Enhanced Thematic Mapper Plus (ETM+), Landsat 4-5 Thematic Mapper (TM)*, and Landsat 1-5 Multispectral Scanner (MSS) instruments.

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The implementation of Collections represents a significant change in the management of the Landsat Archive by ensuring consistent quality through time and across instruments, along with additional changes like metadata and file names. Landsat Science Products inherit characteristics of the Landsat Collection 1 Level-1 data products.

* Some Landsat 4-5 Thematic Mapper (TM) data acquired between 1984 and 1989 cannot be processed by LPGS and added to the Collection 1 Level-1 dataset. Visit the Landsat Processing Systems page for more information about these scenes. 

Collection 1 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_L1GT_037035_20160314_20160314_01_RT
Tier 1: LE07_L1TP_016039_20040918_20160211_01_T1
Tier 2: LT04_L1GS_017036_19821115_20160315_01_T2

Collection 1 Product Identifiers

Landsat Collection 1 product identifiers include the Collection processing levels, processing date, Collection number, and Collection tier category. 

Landsat Collection 1 Product Identifier

The legacy Landsat scene ID that was used before Collection 1 processing remains visible for each scene on EarthExplorer metadata pages, as well as in the metadata file (MTL.txt) that is delivered with the Level-1 data product.  It can also be entered onto the the EarthExplorer Additional Criteria tab when conducting searches. 

 

Changes Applied During Collection 1 Processing

Along with the Landsat Product Identifier, Collection 1 processing created addtional files to Level-1 products, and also added important fields to the metadata file. In addition, a new cloud cover algorithm was applied to Collection 1 Level-1 data.  

New Files included in Collection 1 Level-1 data products
Quality Assessment (QA) bands (NEW to Landsat 1-5 MSS, Landsat 4-5 TM and Landsat 7 ETM+; UPDATED for Landsat 8 OLI/TIRS)
Solar Illumination and Sensor Viewing Angle Coefficient Files (Landsat 4-5 TM, Landsat 7 ETM+, and Landsat 8 OLI/TIRS)

Additional Metadata (MTL.txt) fields
The Saturation Bits parameter identifies which bands contain saturated pixels (Landsat 4-5 TM, Landsat 7 ETM+, Landsat 8 OLI/TIRS)
Land cloud cover assessment estimates the percent of the land in a scene that is covered by clouds (Landsat 4-7)

New Cloud Cover Algorithm
The C Function of Mask (CFMask) algorithm identifies fill, cloud, cloud confidence, cloud shadow, and snow/ice in Landsat 4-5, Landsat 7, and Landsat 8 scenes for representation in the Quality Assessment (QA) band.

Specific for Landsat 8 OLI/TIRS
In February 2017 an algorithm was developed and implemented into the Landsat Product Generation System (LPGS) to correct for the Thermal Infrared Sensor (TIRS) stray light issue and reduced radiance errors. Landsat 8 Data Users Handbook (Appendix A) provides details about the issue and resolution. Users may also find the following journal articles useful about this topic:

Gerace, A. and Montanaro, M. 2017.  Derivation and validation of the stray light correction algorithm for the thermal infrared sensor onboard Landsat 8. Remote Sens. Environ. 191, 15, 246-257.

Montanaro, M., Gerace, A., and Rohrbach, S. 2015. Toward an operational stray light correction for the Landsat 8 Thermal Infrared Sensor, Appl. Opt. 54, 3963-3978.

Montanaro, M., Gerace, A., Lunsford, A., and Reuter, D. 2014. Stray Light Artifacts in Imagery from the Landsat 8 Thermal Infrared Sensor. Remote Sens. 6, 10435-10456.

Specific for Landsat 4-5 TM
"No-Payload Correction Data (PCD)" scenes. Over 260,000 Landsat 5 TM scenes acquired between January 1986 and December 1999, originally downlinked to international ground stations, lack the necessary PCD. Until recently, these scenes failed Landsat Level-1 data processing and could not be added to the Landsat data inventory. However, recent processing algorithm changes made it possible to process the majority of these scenes into the Landsat Collection 1 data inventory and make them available for download.

Specific for Landsat 1-5 MSS 
Landsat 1-5 MSS data have historically proved challenging to Landsat Level-1 processing systems. Many MSS scenes have missing scan lines and other anomalies and artifacts

A number of MSS scenes from 1977 and 1978, (as well as all MSS 5 data acquired from 1995 to 1999 and 2012- 2013) do not contain data in all four band files delivered in the Level-1 product (see this file for a list of scenes with missing data). 

The effort to process Landsat MSS data into Collection 1 required data processing changes to influence the geometric and radiometric accuracy of the Level-1 data products. The Landsat 1-5 MSS Collection 1 page provides in-depth information about the work done to successfully process Landsat MSS data into the Collection 1 archive.

Processing Level Designation Changes
The table below displays the Landsat Collection 1 Level-1 processing levels.

Landsat Collection 1 Level-1 Processing Levels

Standard Terrain Correction (L1TP) data are radiometrically calibrated and orthorectified using GCPs and a DEM to correct for elevation displacement. Ground control points used for L1TP correction are derived from the Global Land Survey 2000 (GLS2000) data set. Landsat processing DEM sources include:

Systematic Terrain Correction (L1GT) data are radiometrically calibrated and with systematic geometric corrections applied using onboard spacecraft data, and DEM data to correct for elevation displacement.  Note: L1GT are the highest level of radiometric calibration and systematic correction possible for Landsat 7 and Landsat 8 scenes collected over Antarctica. The L1GT product uses the high-resolution Radarsat Antarctic Mapping Project (RAMP) Version 2 as the elevation correction source.

Systematic Correction (L1GS) data are radiometrically calibrated but with only systematic geometric corrections applied using onboard spacecraft ephemeris data.

Standard Processing Parameters

All Landsat 1-8 Collection 1 Level-1 are produced by the Landsat Product Generation System (LPGS) using the following parameters:

  • Georeferenced Tagged Image File Format (GeoTIFF)
  • Cubic convolution (CC)
  • Universal Transverse Mercator (UTM) map projection (Stereographic is used for scenes with a center latitude greater than or equal to -63.0 degrees)
  • World Geodetic System (WGS) 84 datum
  • MAP (North-up) image orientation

Landsat Level-1 data are distributed as scaled and calibrated digital numbers (DN). The DN’s can be scaled to absolutely calibrated radiance or reflectance values using metadata which are distributed with the product. Formulas and information on converting Level-1 data to Top-of-Atmosphere radiance, reflectance, or brightness temperature can be found on the Using the USGS Landsat Level-1 Data Product page. 

The Landsat Geometry web page provides additional information on the Landsat Level-1 processing levels, and includes details about GCP updates, DEM, and PCD.

 

Calibration Parameter File (CPF) Name Changes

Calibration Parameter Files (CPF) provide radiometric and geometric coefficients needed for processing of raw, uncorrected Landsat image data. Each timeframe specific CPF contains calibration coefficients that have been adjusted to correct for the time varying performance of the sensor.

 

Response Linearization Look Up Tables (RLUT) Name Changes (Landsat 8 only)

Response Linearization Look Up Tables (RLUT) are additional files that accompany Calibration Parameter Files (CPF) and contain a mapping look up table to linearize the output of the OLI and TIRS detectors.   

 

Data Access

Landsat Collection 1 Level-1 data are available for download from EarthExplorerGloVis, and the LandsatLook Viewer. The data are located under the Landsat category, Landsat Collection 1 Level-1 subcategory, and listed as Landsat 8, Landsat 7, Landsat 4-5 TM, and Landsat 1-5 MSS datasets. 

The EarthExplorer "Additional Criteria" tab for each Collection 1 dataset allows users to select parameters for each Landsat sensor (i.e., Landsat 7 SLC-on/SLC-off, T1/T2/RT, or RMSE range).