December 2017 - AGU Conference Edition
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Landsat Collection 1 Level-1 Data Products
U.S. Landsat Analysis Ready Data (ARD)
U.S. Landsat ARD Special Issue Call for Manuscripts
Landsat Science Products
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Landsat Collection 1 Level-1 Data Products
In 2016, the USGS began reorganizing the Landsat archive into a formal tiered data Collection structure to ensure that Landsat Level-1 data provide a consistent archive of known data quality to support time-series investigative analyses and data “stacking”.
The Collection definition consists of three categories: Tier 1, Tier 2, and Real-Time. Data in Tier 1 meet formal geometric and radiometric quality criteria. Tier 2 do not meet the Tier 1 criteria. The Real-Time Tier contains data immediately after acquisitions and use estimated processing parameters. Once final parameters are available, Real-Time data are reprocessed and assessed for inclusion into Tier 1 or Tier 2, and removed from the Real-Time tier.
Collection 1 initially consists of Landsat Level-1 products generated from Landsat 4-5 Thematic Mapper (TM), Landsat 7 Enhanced Thematic Mapper Plus (ETM+), and Landsat 8 Operational Land Imager (OLI)/Thermal Infrared Sensor (TIRS) instruments. Landsat 1-5 Multispectral Scanner (MSS) data pose their own challenges and will be processed into the Collection 1 inventory after data quality analysis and processing level investigations have been completed.
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 such as metadata and file names. Landsat Science Products inherit characteristics of the Landsat Collection 1 Level-1 data products.
Visit the Landsat Collections webpage for further information.
U.S. Landsat Analysis Ready Data (ARD)
U.S. Landsat Analysis Ready Data (ARD) are products that make the Landsat archive more accessible, easier to analyze, and reduce the amount of time users spend on data processing for time series analysis. U.S. Landsat ARD are derived from Landsat Collection 1 Level-1 precision and terrain-corrected scenes which are further processed and arranged in geospatially-calibrated tiles and dense temporal stacks for immediate use for monitoring and assessing landscape change.
U.S. Landsat ARD are the first USGS data to be placed into the ARD tile grid-based structure. Figure 1 depicts the tile grid structure, how the selected tiles align over Landsat scenes, and how time-series data stacks can be created. Figure 1 above shows the ARD tile grid structure, how the selected tiles (blue squares) align over Landsat scenes (red square), and how time-series data stacks can be created.
U.S. Landsat ARD are available for the conterminous United States, Alaska, and Hawaii using the following Landsat Collection 1 Level-1 data:
- Landsat 8 Operational Land Imager (OLI)/ Thermal Infrared Sensor (TIRS) Tier 1, Tier 2
- Landsat 7 Enhanced Thematic Mapper Plus (ETM+) Tier 1
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Landsat 4-5 Thematic Mapper (TM) Tier 1
Eventually, Landsat 1-5 Multispectral Sensor (MSS) data will also be included in the ARD product suite once these data have been processed into the Landsat Collection inventory structure.
Global Landsat ARD specifications are being developed and will be announced by the USGS once these are finalized.
U.S. Landsat ARD are processed to a common tiling scheme, with each tile containing 5,000 x 5,000 30-meter pixels, and includes all the pixels acquired in a given day within its extents. The ARD tile pixel dimension (number of columns and rows) is smaller than the dimensions of an individual Landsat acquisition.
- 420 tiles cover the land mass extent of the conterminous United States (CONUS)
- 110 tiles cover the land mass extent of Alaska
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8 tiles cover the islands of Hawaii
U.S. Landsat ARD products consist of the following data, which are gridded to a common cartographic projection, and accompanied by metadata to enable further data processing for the user while also retaining data provenance:
- Top of atmosphere (TA) reflectance
- Top of atmosphere brightness temperature (BT)
- Surface reflectance (SR)
- Pixel quality assessment (QA)
- Full-resolution browse image
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Metadata in XML format
Additional information about ARD data products and associated files can be found in the U.S. Landsat ARD Data Format Control Book (DFCB). [Check out the U.S. Landsat ARD frequently-asked questions.]
U.S. Landsat ARD products are available for search and download from EarthExplorer and is the first dataset listed under the Landsat section on the Data Set tab:
U.S. Landsat ARD documentation and other useful resources are located on the ARD webpage.
U.S. Landsat ARD Special Issue Call for Manuscripts
Remote Sensing is seeking manuscripts for a special issue on the Science of Landsat Analysis Ready Data (ARD) that aims to explore the new generation of Landsat science data products that were released by the USGS in October 2017. The topics this journal issue is looking to address include:
- Tools and algorithms for visualizing and analyzing U.S. Landsat ARD
- Suitability of U.S. Landsat ARD for mapping and monitoring land and water dynamics
- Current status and planned/operational U.S. Landsat ARD products
- Specifications and characteristics of U.S. Landsat ARD, including geometric and radiometric consistency
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Combined use of U.S. Landsat ARD and other sensor data (e.g., Sentinel-2, LIDAR, microwaves, thermal scanners) and fusion approaches
Manuscript submissions are due July 31, 2018.
For more information, visit http://www.mdpi.com/journal/remotesensing/special_issues/landsat_ard.
Landsat Science Products
Landsat Level-2 Science Products can be used to document changes to Earth's terrestrial environment and provide an authoritative basis for regional to continental scale identification of historical human and natural induced environmental change, monitoring current conditions, and helping to project future scenarios.
Currently, atmospherically-corrected Surface Reflectance data and Surface Reflectance-derived spectral indices for Landsat Level-1 data from most scenes acquired from August 1982 to present are available.
Surface Reflectance data can be requested from EarthExplorer using the Landsat Collection 1 Level-2 (On-Demand) dataset (shown on Figure 2 on page 3).
The Earth Resources Observation and Science (EROS) Center Science Processing Architecture (ESPA) on-demand interface allows Surface Reflectance ordering of Landsat 4-5 TM, Landsat 7 ETM+, and Landsat 8 OLI/TIRS scenes. Landsat 7 and Landsat 8 scenes are normally available for Surface Reflectance within one week of acquisition.
After uploading a scene list text file (.txt), several options can be selected, including:
- Source products (Original input Level-1 product or metadata)
- Top of atmosphere (TOA) reflectance, surface reflectance (SR), or top of atmosphere brightness temperature (BT) products
- SR-based spectral indices (NDVI, EVI, SAVI, MSAVI, NDMI, NBR, NBR2)
- Customizable output options: data format, reprojection, modifying the image extents, and pixel resizing
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Inter-comparison and output product statistics plotting
All orders submitted through ESPA are processed within 1-3 days, depending on the size of the order. Email notifications are sent to the user after the order is placed, and also after the data is processed and available to download.
Visit this page for more information about Landsat Science Products.