Landsat Update

April 2018 - AAG Conference Edition

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The Landsat Update is an informal communication tool, prepared periodically and distributed electronically to USGS Landsat partners, to provide information about Landsat activities and related topics of interest.

 

 

Landsat 9 Development Status

Landsat 9 is currently in Phase C (final design and fabrication) of the mission development and life cycle. All aspects of the ground, launch and space segments are on track for a scheduled launch readiness date of December 2020.  

Visit the Landsat 9 web page for more details.

A timeline of the Landsat 9 mission development and lifecycle.

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 approximate processing parameters. Once final parameters are determined, Real-Time data are reprocessed and assessed for inclusion into Tier 1 or Tier 2 and removed from the Real-Time tier.

Landsat 8 Operational Land Imager (OLI)/Thermal Infrared Sensor (TIRS), Landsat 7 Enhanced Thematic Mapper Plus (ETM+), and Landsat 4-5 Thematic Mapper (TM) scenes have already been processed to Collection 1; Landsat 1-5 Multispectral Scanner (MSS) data are currently being processed and will become available for download this summer.

The implementation of Collections represents a significant change in the management of the Landsat Archive by ensuring consistent quality through time and across all instruments, along with additional changes such as new Level-1 metadata, revised file names and integration of the TIRS stray light correction algorithm. 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. The image below 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. 

Example visualization of U.S. Landsat Analysis Ready Data tile-based structure and time-series stacking.

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
  • Landsat 4-5 Thematic Mapper (TM) Tier 1

Landsat 1-5 Multispectral Sensor (MSS) data will be considered for addition into 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 when 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.

U.S. Landsat Analysis Ready Data Tile Specifications

Currently, 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
  • Metadata in XML format

Later in 2018, Surface Temperature (ST) data will be added to the ARD product suite.

U.S. Landsat ARD products are available for search and download from EarthExplorer, listed under the Landsat section on the Data Set tab.  Additional information about the Landsat ARD data product can be found on the U.S. Landsat 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
  • 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 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, Level-2 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.

Later in 2018, Level-2 Surface Temperature (ST) and Level-3 Dynamic Surface Water Extent (DSWE) data will become available. Information on these products will be linked from the Landsat Science Products webpage.

Surface Reflectance data can be requested from EarthExplorer using the Landsat Collection 1 Level-2 (On-Demand) dataset (See Figure 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 Landsat 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: file format, reprojection, modifying the image extents, and pixel resizing
  • 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.

Sentinel-2B Data Now Available from USGS EROS

The new Sentinel-2B multispectral imagery is equivalent to the Sentinel-2A data already being acquired to provide potential revisit coverage of the Earth’s global land surfaces every five days. The Sentinel-2A and Sentinel-2B products can be accessed together through the USGS Sentinel-2 data collections on EarthExplorer, GloVis, and Sentinel2Look Viewer.

The Sentinel-2 multispectral imager (MSI) products from USGS consist of Level-1C (top-of-atmosphere) corrected imagery that is highly complementary to the USGS Landsat 8 Operational Land Imager (OLI) and Landsat 7 Enhanced Mapper Plus (ETM+) products.

For more information:
USGS Sentinel-2 Distribution - https://eros.usgs.gov/sentinel-2
ESA Sentinel-2 Mission - https://sentinel.esa.int/web/sentinel/missions/sentinel-2
 
For data access:
EarthExplorer - https://earthexplorer.usgs.gov/
GloVis - https://glovis.usgs.gov/
Sentinel2Look Viewer - https://landsatlook.usgs.gov/sentinel2/

 

Note: Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

 

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