r.drain Traces a flow through an elevation model on a raster map. Raster (r.*) ParameterRaster|input|Elevation|False ParameterString|start_coordinates|Map coordinates of starting point(s) (E,N)|(0,0) ParameterMultipleInput|start_points|Vector layer(s) containing starting point(s)|0|True ParameterBoolean|-c|Copy input cell values on output|False ParameterBoolean|-a|Accumulate input values along the path|False ParameterBoolean|-n|Count cell numbers along the path|False OutputRaster|output|Least cost path