Optical high-resolution satellite imagery for the study of the ancient quarries of Hierapolis

The knowledge of the transformations in action on a territory is necessary to correctly plan a policy addressed to territorial requalification and environmental and archaeological preservation. In particular, understanding the long period processes is necessary to distinguish the historical peculiarities of a territory from the results of recent urban planning. Since 2005 in the territory of Hierapolis of Phrygia, the archaeological research involved a massive use of optical high-resolution satellite images. In particular, to position the ancient quarries in the area close to the city, it has been adopted a 2002 QuickBird-2 panchromatic satellite image, which was georeferenced and orthorectified. Moreover, other optical satellite images were helpful for studying single extraction areas of the territory of Hierapolis but also of Laodikeia and Aphrodisias; besides, when the original data were available (QuickBird-2 from 2002, 2005, 2007 and 2009), the images have been treated with different processing methods (i.e. Normalized Difference Vegetation Index and Change Detection) with the aim of highlighting the archaeological features.