The Role of SAR Sensors

Urban areas represent a very complex environment in terms of shape and number of different materials and patterns found in the widest “urban” land cover class. Remote sensors to be used for the analysis of the urban environment are subject to strict requirements with respect to spectral and spatial resolution, as well as to their capability to handle the third dimension. Synthetic aperture radar (SAR) sensors seem to possess all the necessary features to qualify as a suitable candidate, including the three-dimensional (3-D) capabilities granted by the interferometric version of SAR (InSAR). The SAR community has indeed been gaining increasing importance in the urban remote sensing scenario, as testified by a scanning of the papers presented in the various editions of the URBAN conference. In this chapter, the use of SAR in the urban environment is briefly recalled from an historical perspective, then some current, important fi elds of application are outlined in the following subchapters. Finally, several conclusions are drawn.