In order to meet the growing need for environmental protection, management of natural hazards, natural resources conservation and
sustainable agriculture imposed by the European Union, the Walloon Region wishes to enrich its database of geographic reference
data with the large-scale mapping of impervious surfaces. Additionally, as these impenetrable materials such as asphalt, concrete,
brick, and rooftops are considered to be a significant alteration of the quality of the soil as a natural resource (COM 2006,
European directive on soil protection), knowing the exact extent of these impervious surfaces is very important. The CASIM project aims
at mapping these impervious surfaces herein considering different mapping methodologies. Furthermore, at the same time the value
of the existing aerial ortho-images, LIDAR data and different thematic data produced or acquired by the Walloon Government is
assessed for mapping these surfaces. In detail, this study involves two tasks:(i) Mapping of impervious surfaces with existing data,
managed, produced or acquired by the Public Service of Wallonia, including the land use map of Wallonia, the digital soil map, the
PLI, ...(ii) Assessing the feasibility of mapping impervious surfaces in Wallonia with a combination of aerial ortho-photos and
LIDAR data. For this a pilot site was selected in the basin of the river Houille.Different methods of segmentation and image
classification will be identified and tested.