Sensing the Past from Space: approaches to site detection

This chapter is concerned with site detection by using earth observation technologies with particular reference to optical satellite data. Three different approaches are discussed: (1) the reconnaissance, analysis, and interpretation of proxy indicators; (2) remote sensing data integration; and (3) geographic information system (GIS)-based prediction modeling. Most of the chapter is dedicated to proxy indicators and in particular to how recognize them and which kind of data processing can be fruitfully employed for their enhancement. The proxy indicators are the result of physical and chemical interaction between archaeological remains and their surroundings that can produce changes in vegetation, moisture content, and microrelief. The reconnaissance of the proxy indicators is performed by means of the observation and processing of tones, shadows, shapes, textures, and patterns. For each of them some data processing methods (from the computation of spectral indices to semiautomatic and automatic features/object extraction) are shown and discussed with case studies. Two other approaches to site detection are prediction models based on GIS analyses and the integration of different remote sensing data. The prediction models aim at predicting the presence of sites of archaeological sites on the basis of observed patterns and on assumptions about human behavior, to be analyzed with environmental and geographic context, by using remotely sensed imagery and terrain models. Finally, different opportunities to integrate passive and active remotely sensed data to improve the characterization of microtopographic features related to shallow remains and the identification of paleo-environmental features are shown and discussed.