r.walk Outputs a raster layer showing the anisotropic cumulative cost of moving based on friction cost. Raster (r.*) ParameterRaster|elevation|Elevation raster layer|False ParameterRaster|friction|Friction costs layer|False ParameterVector|start_points|Starting points|-1|False ParameterString|max_cost|An optional maximum cumulative cost|0 ParameterString|percent_memory|Percent of map to keep in memory|100 *ParameterString|walk_coeff|Coefficients for walking energy formula parameters a,b,c,d|0.72,6.0,1.9998,-1.9998 *ParameterString|lambda|Lambda coefficients for combining walking energy and friction cost|1.0 ParameterString|slope_factor|Slope factor determines travel energy cost per height step|-0.2125 *ParameterBoolean|-k|Use the 'Knight's move'; slower, but more accurate|True *ParameterBoolean|-n|Keep null values in output map|True *ParameterBoolean|-r|Start with values in raster map|True OutputRaster|output|Cost