USGS EROS Archive - Landsat Legacy - Landsat 7 ETM+ Collection 1 Legacy Samples
Landsat Collection 1 Legacy Samples preserve a selection of data from the first Landsat Collection. These samples provide essential benchmarks for researchers, ensuring historical data remains available for comparison and can be used to evaluate quality improvements across collections.
Dataset Citation
Please cite this dataset in the following manner:
Earth Resources Observation and Science (EROS) Center. Landsat 7 Enhanced Thematic Mapper Plus Level-1, Collection 1 Legacy Sample https://doi.org/10.5066/P1DUKNQV
Purpose of Legacy Samples
Landsat Collection 1 products were removed from public access in December 2022. In 2023, a subset of Landsat 1-8 Collection 1 data— including Level-1, U.S. Analysis Ready Data (ARD) and operational Landsat Level-3 science products— were carefully selected and retained. These Legacy Samples support science quality assessment, data processing algorithm chain testing, and cross-collection comparisons.
Note: The Collection 1 Legacy Samples are intended for software testing and cross-collection comparison only. For current scientific studies, Landsat Collection 2 products, available from 1972 to present, are the recommended data source.
Location Selection Rationale
The locations of the Legacy Samples were selected based on atmospheric and surface conditions – most notably, at proven instrumented reference test sites where regular in-situ calibration measurements are available. Coastal and inland water locations, as well as areas of recurring data anomalies were also included. Additionally, random samples were selected to represent a proportional ratio to the total available products from each Landsat sensor.
The following criteria was established for inclusion in Landsat Collection 1 Legacy Samples:
- Represent a percentage of data from each satellite sensor.
- Ensure global distribution as evenly as possible.
- Include validation products that enable regeneration of satellite calibrations required to maintain a record for cross-collection comparisons (e.g. geometric and radiometric accuracy, atmospheric compensation).
- Include products that cross the Antemeridian (+/-180-degree Longitude), products designated for future U.S. ARD testing, and products in areas known to cause ground systems issues so they can be identified and addressed during future ground system software development.
- Include random products for testing system bulk processing.
Legacy Samples Product Overview
The Landsat Collection 1 Legacy Samples dataset includes the following products from Landsat 1 through Landsat 8, spanning data acquired from July 1972 to December 2021. The Legacy Samples are now available from the USGS archive.
Samples from newer collections will also become available in the future.
Level-1 Products
A total of 11,351 Landsat Level-1 scene-based products (less than 0.1 % of the entire USGS Landsat Collection 1 Level-1 archive) were selected for the Landsat Legacy Samples dataset. Based on the product selection rationale described above, the breakdown is as follows:
- About 30% are from known and potential satellite Calibration/Validation site areas, as well as areas used for cloud validation/cloud masks development.
- About 15% are from sites known to cause issues with ground systems.
- The remaining 55% are randomly selected daytime, on-nadir scenes with less than 30% cloud cover.
Additional Information
Access Data
The Landsat 7 Enhanced Thematic Mapper Plus Level-1, Collection 1 Legacy Sample are available for download from EarthExplorer.
The data are located under the "Landsat" category, "Landsat Legacy subcategory", as "Landsat 7 ETM+ C1 L1 Sample".
After reviewing the search results and selecting a scene, users will be able to download data. The USGS Landsat no-cost and open data policy remains intact since its inception in 2008.
Data Citation History
Please cite this dataset in the following manner: Earth Resources Observation and Science (EROS) Center. Landsat 7 Enhanced Thematic Mapper Plus Level-1, Collection 1 Legacy Sample [dataset]. U.S. Geological Survey. https://doi.org/10.5066/P1DUKNQV
Landsat Collection 1 Legacy Samples preserve a selection of data from the first Landsat Collection. These samples provide essential benchmarks for researchers, ensuring historical data remains available for comparison and can be used to evaluate quality improvements across collections.
Dataset Citation
Please cite this dataset in the following manner:
Earth Resources Observation and Science (EROS) Center. Landsat 7 Enhanced Thematic Mapper Plus Level-1, Collection 1 Legacy Sample https://doi.org/10.5066/P1DUKNQV
Purpose of Legacy Samples
Landsat Collection 1 products were removed from public access in December 2022. In 2023, a subset of Landsat 1-8 Collection 1 data— including Level-1, U.S. Analysis Ready Data (ARD) and operational Landsat Level-3 science products— were carefully selected and retained. These Legacy Samples support science quality assessment, data processing algorithm chain testing, and cross-collection comparisons.
Note: The Collection 1 Legacy Samples are intended for software testing and cross-collection comparison only. For current scientific studies, Landsat Collection 2 products, available from 1972 to present, are the recommended data source.
Location Selection Rationale
The locations of the Legacy Samples were selected based on atmospheric and surface conditions – most notably, at proven instrumented reference test sites where regular in-situ calibration measurements are available. Coastal and inland water locations, as well as areas of recurring data anomalies were also included. Additionally, random samples were selected to represent a proportional ratio to the total available products from each Landsat sensor.
The following criteria was established for inclusion in Landsat Collection 1 Legacy Samples:
- Represent a percentage of data from each satellite sensor.
- Ensure global distribution as evenly as possible.
- Include validation products that enable regeneration of satellite calibrations required to maintain a record for cross-collection comparisons (e.g. geometric and radiometric accuracy, atmospheric compensation).
- Include products that cross the Antemeridian (+/-180-degree Longitude), products designated for future U.S. ARD testing, and products in areas known to cause ground systems issues so they can be identified and addressed during future ground system software development.
- Include random products for testing system bulk processing.
Legacy Samples Product Overview
The Landsat Collection 1 Legacy Samples dataset includes the following products from Landsat 1 through Landsat 8, spanning data acquired from July 1972 to December 2021. The Legacy Samples are now available from the USGS archive.
Samples from newer collections will also become available in the future.
Level-1 Products
A total of 11,351 Landsat Level-1 scene-based products (less than 0.1 % of the entire USGS Landsat Collection 1 Level-1 archive) were selected for the Landsat Legacy Samples dataset. Based on the product selection rationale described above, the breakdown is as follows:
- About 30% are from known and potential satellite Calibration/Validation site areas, as well as areas used for cloud validation/cloud masks development.
- About 15% are from sites known to cause issues with ground systems.
- The remaining 55% are randomly selected daytime, on-nadir scenes with less than 30% cloud cover.
Additional Information
Access Data
The Landsat 7 Enhanced Thematic Mapper Plus Level-1, Collection 1 Legacy Sample are available for download from EarthExplorer.
The data are located under the "Landsat" category, "Landsat Legacy subcategory", as "Landsat 7 ETM+ C1 L1 Sample".
After reviewing the search results and selecting a scene, users will be able to download data. The USGS Landsat no-cost and open data policy remains intact since its inception in 2008.
Data Citation History
Please cite this dataset in the following manner: Earth Resources Observation and Science (EROS) Center. Landsat 7 Enhanced Thematic Mapper Plus Level-1, Collection 1 Legacy Sample [dataset]. U.S. Geological Survey. https://doi.org/10.5066/P1DUKNQV