Starting the week of January 11, 2016, data for the affected path/rows will be reprocessed to implement the new GCPs.
Phase 2 includes updating 1,151 WRS-2 paths/rows, covering island areas and inland regions where the estimated absolute accuracy of the original Global Land Survey 2000 (GLS2000) ground control varied between 50 to 75 meters. This will update GCPs in middle to low latitude regions and also includes improvements to GCPs for Australia for greater consistency with the Australian Geographic Reference Image (AGRI).
A list of paths/rows affected is available. Because the updated GCPs will be more accurate, and may allow scenes that once could only be processed to a systematic L1GT product to be processed as a precision L1T product, users may want to consider replacing previously downloaded images for these areas.
Users can review the metadata file (MTL.txt) delivered with the reprocessed scenes to determine the following updates to indicate newly processed data:
- The GROUND_CONTROL_POINTS_VERSION parameter will display version number “3”: [GROUND_CONTROL_POINTS_VERSION=3]
- The FILE_DATE will be updated with a date after January 11, 2016
The “dateUpdated” column of files downloaded from the Landsat Bulk Metadata Service will reflect the date of the newly processed data.
Landsat 8 scenes in affected path/rows will finish reprocessing before Landsat 1-7 MSS and TM scenes. Overall time to reprocess all affected scenes (over 500,000) will take 4-6 weeks. Another message will be posted when Phase 2 Ground Control Points reprocessing is complete.
