Automated extraction of shoulder line of valleys based on flow paths from grid Digital Elevation Model （DEM） data

The extraction of a continuous shoulder line of valleys with a precise location is a critical technique in constructing the mechanism-process models of spatial distribution‚such as those for soil erosion‚sediment transportation and runoff process in gully areas of the Loess Plateau．The extraction technique presented in this paper is based on a hydrological method of river network and catchment boundary extraction‚utilizing slope variation of a flow path to define the feature segment of slope profile and produce a continuous shoulder line of valleys．In this paper‚the authors presented an algorithm‚by which the drainage network and the continuous shoulder line of valleys were extracted automatically from the DEM of Caijiachuan watershed in Jixian County‚ Shanxi Province‚which is located in the gully area of the Loess Plateau．The final result agrees with the optical interpretation from slope distribution in the experimental area．