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The areas affected include island and coastal locations, where meager coverage existed (lack of reference data in the original triangulation, few GCPs available, etc.), desert regions where shifting dunes caused existing GCPs to become obsolete, and other anomalous locations in which an apparent bias remained.
Because the updated GCPs are more accurate, users should consider re-ordering previously downloaded images. Scenes that once processed to a systematic L1G or L1Gt may now process to a precision L1T product. The offsets are significant for many of the scenes, which may affect time series analysis.