MULTIRESOLUTION ANALYSIS OF RADAR IMAGES AND ITS APPLICATION TO LITHOLOGICAL AND STRUCTURAL MAPPING - LARZAC (SOUTHERN FRANCE) TEST SITE

The differentiability of surfaces on Radar imagery is dependent on the parameters of the imaging system such as wavelength, polarisation, re solution, as well as on soil characteristics, geomorphology, and the g eometric conditions during imaging. In this research, to study the eff ects of pixel size on geological mapping using C-band data, several im ages of different resolutions have been simulated from an E-SAR airbor ne radar image acquired by the German space agency, Deutsche Luft und Raumfahrt (DLR). Owing to the tendency of rough relief causing large g eometric distortions and high radiometric contrasts on radar images, i t is almost impossible to employ these for purposes other than geomorp hology. This is why we have chosen a study zone with moderate relief-t he 'Causse de Larzac' in Southern France. Comparative studies carried out have shown that the (2 m; 2.2 look) configuration at 1/20 000 scal e is suitable for the mapping of lithological units and major regional structural traces, and that the (4 m; 5 look) configuration seems equ ally suitable. From these configurations, a reference map was generate d and a number of geological features identified for use in evaluating the quality of other available resolutions.