The Phoenix, Arizona metropolitan area, also known as the Valley of the Sun, is comprised of more than 14,600 square miles and is considered the largest metropolitan area in the southwestern United States. The desert climate and abundant sunshine of the area are main factors in population growth and urban sprawl.
Landsat Calibration & Validation
While Landsat satellites are well-designed and calibrated prior to launch, continuous calibration is required to offset degradation that may be caused by mechanical or electrical effects, or exposure to UV radiation. Calibration requires a comparison between the measuring instrument and an absolute reference standard of known accuracy. Validation of Landsat data is an ongoing effort.
EROS Cal/Val Center of Excellence (ECCOE)
EROS Cal/Val Center of Excellence (ECCOE)
The calibration of Landsat sensors is supported by pre-flight, post-launch onboard, and ground reference data, which is continually researched and updated by the ECCOE Team, alongside funded university partners working in vicarious calibration. Ground control and elevation validation is applied to data acquired by Landsat sensors, resulting in the highest quality products.
Calibration/Validation Reports
Calibration/Validation Reports
The ECCOE Landsat Cal/Val Team continually monitors the geometric and radiometric performance of active Landsat missions and makes calibration adjustments as needed to maintain data quality at the highest level. Results of the analysis are summarized in quarterly USGS Open File Reports.
Known Satellite, Sensor, Data Issues
Known Satellite, Sensor, Data Issues
Landsat data are systematic, geometric, radiometric, and terrain corrected to provide the highest quality data. Occasionally, anomalies occur, and artifacts are discovered that require research and monitoring. The Landsat Cal/Val team investigates and tracks anomalous data and monitors satellite sensors for changes.
Maintaining the Gold Standard in Earth Observations
Continuity with the past is key to meeting future land imaging science needs. The Landsat program is the longest continuous record of satellite-based Earth imaging. Landsat data quality is viewed by the remote-sensing user community as the "Gold Standard" (National Geospatial Advisory Committee, 2020).
To ensure the continued excellent quality of Landsat data, the USGS Earth Resources Observation and Science (EROS) Center has identified the following key strategic pillars:
- Maintain a well-calibrated multidecade remote-sensing archive for science applications and Earth observation advancement.
- Develop and understand land remote-sensing requirements and land imaging solutions.
Understanding the land imaging requirements of current and future users, along with an ability to assess the capabilities of current and future systems for meeting those requirements, is key to meeting future land imaging science needs.
In the past, the Cal/Val activities addressing the pillars noted above were spread across multiple groups. The EROS Cal/Val Center of Excellence (ECCOE) was established in 2018 to enable the USGS to more efficiently address national and global land remote-sensing needs.
The ECCOE Landsat Cal/Val Team continually monitors the radiometric performance of active Landsat missions and makes calibration adjustments as needed. Continual geometric corrections are made to ensure Landsat data are of the highest quality.
Landsat 9 pre-launch, commissioning, and early on-orbit performance highlighted in journal
A recently published Remote Sensing Special Issue provides information on the calibration and validation activities performed that ensure the gold standard of geometric, radiometric, spatial, and spectral resolutions are upheld, and lead to known and expected superior Landsat 9 data quality. Topics cover pre-launch characterization, testing, commissioning, and early on-orbit performance for the OLI and TIRS instrument and Landsat 9 spacecraft. Visit the Remote Sensing webpage to view the published papers within this issue.
Radiometric Calibration/Validation
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Factors like sensor artifacts, viewing and illumination angles, or atmospheric conditions affect Landsat data's digital number (DN) values.
Monitoring and regular characterization of sensor data are required to maintain radiometric calibration and stability of Landsat products and improve algorithms and processes used in product generation.
Access the Landsat Radiometry webpage to learn more.
Geometric Calibration/Validation
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Accurate geometry ensures that Landsat data pixels are aligned and that the data can be used easily in time series analysis through the use of ground control points, processing levels, and spatial performance tests.
The exceptional geometric qualities of Landsat 8 and Landsat 9 OLI/TIRS data are used to improve the reference database used to precisely and accurately geolocate all Landsat Level-1 data products.
Access the Landsat Geometry webpage to learn more.
Calibration Files Used in Landsat Product Generation
Calibration Files Used in Landsat Product Generation
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Landsat Calibration Parameter Files
Calibration Parameter Files (CPFs) 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.
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What are Landsat Bias Parameter Files?
Landsat Bias Parameter Files (BPFs) supply radiometric correction parameters that are applied during Level-1 processing of Landsat data. Learn more (and search for BPF files): Landsat Bias Parameter
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What are Landsat Response Linearization Look Up Tables?
Landsat Response Linearization Look Up Tables (RLUT) are additional files that accompany Calibration Parameter Files (CPFs) and contain a mapping lookup table to linearize the output of the Landsat 8 and Landsat 9 Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS) detectors. Learn more (and download RLUT files): Landsat Response Linearization Look Up Tables
Landsat Mission Underfly Opportunities
Cross-calibration between instruments is the best method to standardize Landsat sensors. As a newly launched satellite makes its way to its final orbit, opportunities to acquire imagery near-coincidentally in tandem with an earlier mission sensor allows USGS and NASA Landsat Cal/Val staff to ensure the new sensors are accurately calibrated and characterized. Underfly opportunities have been successful since Landsat 4 and Landsat 5 flew in tandem during an underfly campaign on March 15-16, 1984 following the Landsat 5 launch.
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Visit the Landsat Mission Underfly Opportunities webpage for details and to view pictures from each of the historic underfly events.
Additional Calibration Information
Additional Calibration Information
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Solar Illumination and Sensor Viewing Angle Coefficient Files
Landsats 4-9 Level-1 products contain an angle coefficient file (“_ANG.txt”). This file consists of per-pixel solar (sun) and sensor (satellite, view) azimuth and zenith values to be used in conjunction with the pixel values for each of the bands in the Landsat Collection 2 Level-1 product.
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ECCOE Landsat Quarterly Calibration and Validation Reports
The USGS EROS Cal/Val Center of Excellence (ECCOE) Landsat Cal/Val Team continually monitors the geometric and radiometric performance of active Landsat missions and makes calibration adjustments as needed to maintain data quality at the highest level. Results of the analysis are summarized in quarterly USGS Open File Reports.
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Landsat Known Issues
This page provides information about Landsat sensor anomalies that impact the mission-level data and subsequent Collections.
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Test Sites Catalog
The number of Earth-observing sensors and their derived science products continue to grow rapidly. Without characterization and calibration of these sensors, the products they provide could not be reliably used by scientists and decision makers.
Related
Landsat 9 Image of Phoenix Metropolitan Area
The Phoenix, Arizona metropolitan area, also known as the Valley of the Sun, is comprised of more than 14,600 square miles and is considered the largest metropolitan area in the southwestern United States. The desert climate and abundant sunshine of the area are main factors in population growth and urban sprawl.
Landsat 9 Image of White Sands National Park
The Operational Land Imager (OLI) onboard the Landsat 9 satellite captured this image of the White Sands National Park on May 13, 2024.
The Operational Land Imager (OLI) onboard the Landsat 9 satellite captured this image of the White Sands National Park on May 13, 2024.
Landsat 8 image of the Salton Sea 2023
This Landsat 8 image shows the Salton Sea and surrounding area in California.
Landsat 8
Path 39 Row 37
October 18, 2023
Bands 6,5,4
This Landsat 8 image shows the Salton Sea and surrounding area in California.
Landsat 8
Path 39 Row 37
October 18, 2023
Bands 6,5,4
Landsat's Calibration and Validation
Engineers and scientists from both Landsat and Sentinel missions are working together to calibrate observation data and validate its quality to improve the science using these resources.
Engineers and scientists from both Landsat and Sentinel missions are working together to calibrate observation data and validate its quality to improve the science using these resources.
Related
Landsat 9 Image of Phoenix Metropolitan Area
The Phoenix, Arizona metropolitan area, also known as the Valley of the Sun, is comprised of more than 14,600 square miles and is considered the largest metropolitan area in the southwestern United States. The desert climate and abundant sunshine of the area are main factors in population growth and urban sprawl.
The Phoenix, Arizona metropolitan area, also known as the Valley of the Sun, is comprised of more than 14,600 square miles and is considered the largest metropolitan area in the southwestern United States. The desert climate and abundant sunshine of the area are main factors in population growth and urban sprawl.
Landsat 9 Image of White Sands National Park
The Operational Land Imager (OLI) onboard the Landsat 9 satellite captured this image of the White Sands National Park on May 13, 2024.
The Operational Land Imager (OLI) onboard the Landsat 9 satellite captured this image of the White Sands National Park on May 13, 2024.
Landsat 8 image of the Salton Sea 2023
This Landsat 8 image shows the Salton Sea and surrounding area in California.
Landsat 8
Path 39 Row 37
October 18, 2023
Bands 6,5,4
This Landsat 8 image shows the Salton Sea and surrounding area in California.
Landsat 8
Path 39 Row 37
October 18, 2023
Bands 6,5,4
Landsat's Calibration and Validation
Engineers and scientists from both Landsat and Sentinel missions are working together to calibrate observation data and validate its quality to improve the science using these resources.
Engineers and scientists from both Landsat and Sentinel missions are working together to calibrate observation data and validate its quality to improve the science using these resources.