The environmental sensitivity to oil pollution is addressed in the Loire estuary, an area of very high economical and recreational value. The first part of the paper deals with the evaluation of remote sensing images (SPOT, Landsat Thematic Mapper and ERS-1 radar). The availability of the right images with respect to low tide conditions is discussed. Well-established classifications are used for both visible and radar images, which produce mainly geomorphological information: coastline, sediments, vegetation. Living resources at risk are compiled mostly out of ancillary data, i.e., maps and reports. These two types of information lead to ranking the shoreline in terms of its ecological sensitivity. Man-made objects and human activities are also incorporated. After collecting all relevant data, we examine in a second part how to merge them and produce environmental sensitivity maps, using both CAD (Computer Assisted Design) and GIS (Geographic Information Systems) tools.