The Landsat Project is in the process of improving the ground control points (GCPs) used to georegister Landsat products.
The much higher geolocation accuracy of Landsat 8 makes it possible to significantly improve the absolute accuracy of Landsat data products for all Landsat sensors. For more information about the phased GCP Improvement Plan with details on the Phase 1 GCPs to be released in September, please see the July 1, 2014 Mission Headline.
The new metadata parameter will only be provided for any scene that processes to a Level-1 Precision and Terrain-Corrected (L1T) product (PRODUCT_TYPE = "L1T"). The metadata parameter name for the GCP versioning are provided below:
Group name: IMAGE_ATTRIBUTES
Parameter name: GROUND_CONTROL_POINTS_VERSION
GCP versioning and the release of the Phase 1 GCPs takes effect with Landsat Product Generation System (LPGS) releases identified below and all future releases
PROCESSING_SOFTWARE_VERSION = “LPGS_2.4.0” for Landsat 8 products
PROCESSING_SOFTWARE_VERSION = "LPGS_12.5.0" for Landsat 1-7 products
L1T products created in prior releases will not have the versioning field. See the Landsat L1 Data Format Control Books (DFCB) for more information about the MTL files.
Users can use the GCP version in combination with GCP release notes to determine which scenes are impacted with each version number. A list of the 115 path/rows with GCPs updated in GCP Improvement Phase 1 (GROUND_CONTROL_POINTS_VERSION =”2”) can be found here. All images for path/rows updated in Phase 1 will be removed from the online storage and will be reprocessed. We recommend reordering all images associated with Phase 1 path/rows. Guidance for future releases will be provided at the time of their release.
Please contact Landsat Customer Services with any questions: custserv@usgs.gov
