This paper presents methods to extract badlands thalwegs network from regular grid DTM by combining terrain morphology indices to a drainage algorithm. The computation of a continuous vector network will permit the study of the badlands spatial patterns. These methods aim at delineating a thalweg only where the DTM denotes a significant curvature with respect to DTM accuracy. It relies on three major steps. Firstly, discontinuous concave areas are detected from the DTM using morphological criteria; the plan curvature and the convergence index. Secondly, the concave areas are connected using a drainage algorithm which provides continuous and tree-structured thick scheme. We assume that these areas present physical significance and correspond to a gully floor area. Finally, the thick path is reduced to its main curve and vectorised to obtain a thalwegs network. The methods are applied on both virtual and actual cases DTM. The actual case is a LiDAR DTM of Draix Badlands (French Alps). The obtained networks are quantitatively compared both to the one obtained with usual drainage area criteria and to a reference network. The networks comparison shows the great potential of the convergence index based method for thalwegs network extraction.

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lidar dtm of draix badlands french morphological criteria regular grid dtm discontinuous concave areas one convergence index based method plan curvature drainage area criteria curve continuous vector network thalweg continuous and treestructured thick gully floor thalwegs network extraction badlands spatial patterns thick path methods terrain morphology indices networks

N. Thommeret,J. S. Bailly,C. Puech,.Robust extraction of thalwegs network from DTM: application on badlands. 7 (1),.

N. Thommeret,J. S. Bailly,C. Puech,"Robust extraction of thalwegs network from DTM: application on badlands" 7

N. Thommeret,J. S. Bailly,C. Puech,"Robust extraction of thalwegs network from DTM: application on badlands"