Potential of linear features detection in a Mediterranean landscape from 3D VHR optical data: application to terrace walls
Potentiel des données optiques 3D à très haute résolution pour la détection d'éléments linéaires de paysages cultivés : application aux fronts de terrasses
Résumé
Mediterranean cultivated landscapes are prone to floods, erosion and water pollution. They are also considered as hotspots for biodiversity. As hydraulic and linear artificial settlements, terrace fronts or terrace walls consisting in historic man-made levees on agricultural plot margins, can alter hydrological fluxes, limit erosion, favour soil water storage and biodiversity (habitat and corridor effects) [1]. More and more spatially explicit models and indicators need the map of these landscape linear features to diagnose the hydrological risk or biodiveristy at catchment or region scale [2]. However, terraces walls are almost never mapped in any map agency databases. Therefore, the potential of very high spatial resolution remote sensing data, in 2D or 3D scenes, to map these linear elements, need to be adressed. Some recent studies showed that terraces from 2D VHR scenes, i.e images, can be poorly detected, due to both vegetation cover altering objects visibility having poor spectral signature or due to anisotropic shadowing effects. The use of 3D scenes, i.e. digital terrain models (DTM) and digital surface models (DSM), appears therefore as more reliable.