Detection and description of sand dunes using a geomorphometric approach

International audience; In the last decades, sandbanks and sand dunes of various shapes and sizes have been found anddescribed on continental shelves all over the world. These structures tend to migrate and ourunderstanding of the mechanisms regulating their dynamics is limited. These sandbanks became aconcern due to the fact that they interfere with the human activities at sea. Consequently, theirpresence has economical and environmental impacts. The purpose of this study is to automaticallydetect these dunes in DTMs (Digital Terrain Models) generated from MBES data. So far, automatictechniques aiming at describing marine dune fields have always brought information such as theheight, dune spacing or the orientation at local scale but never went down to a dune scale.Currently, the dunes are still manually digitized and then form parameters are calculated. This task istedious and time-consuming. In addition, the amount of data to process being always bigger, it getsdifficult for operators to keep the pace. To address this issue, we propose a geomorphometricapproach. Attributes such as the slope or curvatures are estimated from DTMs. A combined analysisof the metrics maps enables to extract dunes from their environment. The following step is thedetermination of parameters characterizing the shape and size for each dune. This work providesknowledge about dune fields at a detailed level. Thus, the composition, spatial distribution and otheraspects of sand banks can be obtained. Further research can be conducted in order to learn moreabout the dynamics of dune fields at an individual level.