[Source: USGS Landsat] New Ground Control Points (GCPs) will become available for three WRS-2 path/rows and GCPs contained within large water bodies will be removed on February 3, 2014 to coincide with the Landsat 8 archive reprocessing. As a consequence of the improved GCPs, scenes once created as a systematic Level 1GT (L1GT) product may now process to a precision Level 1T (L1T) product.
Further information:
+ New Ground Control Points for Select Landsat 8 Scenes