Landscape Archaeology in Tuscany: Cultural resource management, remotely sensed techniques, GIS based data integration and interpretation

There is increased interest today in making scientific progress through the use of remotely sensed data in social science research. On this topic it is important to remember that remote sensing is not a new technology. Archaeological studies have a long tradition of aerial photography application, from the earliest air photographs taken from balloons at the end of XIXth century to the crucial works of O.G.S. Crawford and many others aerial archaeologists, until the actually National Mapping Programmes. What is changed in recent years about remote sensing application it is the development of new sensors (in particular multi-spectral, hyper-spectral, microwave) and the availability of new tools for the management and for the integration of spatial information. The Department of Medieval Archaeology at the University of Siena has been actively engaged in programmes of landscape archaeology for over thirty years. Territorial studies have been based for the most part on three methodologies of investigation: field survey in sample areas (with 20-30% of the total landscape and replicated collection); field examination to assess the significance of individual monuments (known roman villa, medieval castles, churches, etc.); and analysis of vertical air photos combined with selective ground-truthing. Since the end of 1998 we turned the attention to increase our experience in remote sensing techniques. Within the Department of Medieval Archaeology, the Laboratory of Aerial Photographic Interpretation has been active since 1984. Despite good archaeological results, we have been conscious throughout of the inherent limitations of this method of survey. The main problem is the cartographic nature of the data and the impossibility of planning the flights to coincide with times when conditions for the detection of archaeological features are at their best. To try and overcome these limitations in pursuit of our own objectives we have changed our focus to the experimental application and evaluation of new techniques in the study of the Tuscan landscape. This is the reason why we turned to oblique aerial photography, to the latest generation of multi-spectral high-resolution satellite imagery (Ikonos-2 and QuickBird-2), to geophysical survey and to micro-digital terrain modelling using differential GPS. Our progress in developing this approach can be highlighted by looking at five sample areas, representative of the landscape complexities and settlement patterns of Tuscany. The total extent of these sample areas is around 670 square km. All areas have recently been the subject of numerous socio-archaeological studies, field-walking surveys, excavations, vertical air-photo interpretation, geological and geomorphologic analysis. When setting up the research project we paid particularly close attention to the systematic collection of data. The first methodological objective of the operation was to arrange the greatest possible number of elements for comparison - using GIS technology - with satellite imagery and with oblique aerial photographs. In a second stage it will be useful to integrate the whole information and porpose new settlement patterns. Even at this early stage, By applying multistage sensing techniques to our landscape projects, we can say that the introduction of this approach, running hand in hand with continuing programmes of field-walking, has transformed both our way of working and our understanding of ancient landscapes increasing the value and impact of our research