Landsat Collections — What are Tiers?

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Detailed Description

This is the third video in a series describing the new U.S. Geological Survey (USGS) Landsat Collection 1 inventory structure. Collection 1 required the reprocessing of all archived Landsat data to achieve radiometric and geometric consistency of Level-1 products through time and across all Landsat sensors. This video explains how Landsat Collection Level-1 data products are organized into one of three tier categories (Real Time, Tier 1 or Tier 2) based on data quality and level of processing. This tiered data Collection structure ensures that Landsat Level-1 products provide a consistent archive of known data quality to support time-series analyses and data “stacking”, while controlling continuous improvement of the archive and access to all data as they are acquired To learn more about Landsat Collections please visit https://landsat.usgs.gov/landsat-collections

The Landsat Program is a series of Earth-observing satellites co-managed by USGS and NASA, and offers the longest continuous space-based record of Earth’s land in existence. Every day, Landsat satellites orbit Earth and provide essential information to help land managers and policymakers make informed decisions about our natural resources and environment. All Landsat data are distributed by the USGS at no charge from EarthExplorer, GloVis, and the LandsatLook Viewer. To learn more about the Landsat Program please visit https://landsat.usgs.gov/ or follow us on Twitter @USGSLandsat or Facebook @NASA.Landsat.

Details

Image Dimensions: 1280 x 720

Date Taken:

Length: 00:02:38

Location Taken: Sioux Falls, SD, US

Video Credits

Content created by Andy Dykstra and Linda Owen (Contractors to USGS EROS)

Transcript

Narration

Within the Landsat Collections, scenes are evaluated and categorized into one of 3 tiers.

Gene Fosnight
The first tier is called real time, and into the real time tier goes all the data immediately after acquisition. And they’re left there until such time as final calibration can be applied to those data sets.

Narration

The real time tier holds newly acquired imagery. This can be useful when monitoring events and natural disasters, where near real time data is critical. Real-time Landsat 8 OLI data is very accurate. However, the thermal bands require additional processing before the scene is placed into the final tier. This processing is applied within 16 days after acquisition. Landsat 7 instrument trending and characterization is applied within 26 days after acquisition, before the data is moved to the final tier.

Gene Fosnight

At that point in time RMSE is used to determine which of either tier 1 or tier 2 those data go into. And we have an RMSE threshold of 12 meters, which dictates whether it goes into tier 1 or tier 2.

Narration

A large majority of new Landsat scenes meet the requirements to be placed into the higher quality tier 1. Some scenes, especially those from previous satellites fall short of the 12 meter RMSE goal, and are categorized into tier 2. These scenes are still valuable in whole or in part, but can be quickly filtered out by users wanting only the best spatial quality. Users interested in Tier 2 scenes can analyze the RMSE and other properties to determine their suitability.

Brian Sauer

So it lets the user easily be able to go through the archive and pick high quality data that really stacks over time. And they know that the provenance is consistent, the data’s processed in a consistent manner and has a specific quality to the data.

Narration

Landsat Collection 1 is the highest quality inventory of Landsat level 1 products ever created. This structure ensures that Landsat data products provide a consistent archive of known quality to support time series analysis and data stacking while controlling continuous improvement of the archive and access to all data as they are acquired.