Corona Satellite Pictures for Archaeological Studies: A Review and Application to the Lost Forbidden City of the Han–Wei Dynasties

This paper provides a state of the art of the use of declassified satellite Corona for archaeological application and deals with the use of historical archives of Corona and aerial photographs for detecting ancient hidden cultural relics that may be completely lost in the modern landscape veiled by current land uses and land covers. Geospatial analysis is adopted to identify, extract and map the subtle archaeological features and cultural landscape of the lost Han-Wei Forbidden City in the Henan Province (China). It was one of the most important cities of ancient China, served as the capital for a long period, from the Eastern Zhou (2600 BP, Zhou Dynasty) to the Eastern Han and Wei Dynasties (1900-1500 BP). Outputs from our investigations clearly provided evidence of numerous buried structures of potential archaeological interest that were compared with historical documentation and excavations carried out in the area. The geospatial analysis, applied both to aerial photograph and to Corona pictures, enabled us to discover a number of unknown sub-palaces and structures, thus providing new insights for this important archaeological area.