Tool Upslope and Downslope Curvature

This tool first calculates the local curvature of a cell as sum of the gradients (i.e. tangens of slope) to its neighbour cells. This is a simple estimation of the general curvature and is strongly correlated with general curvatures calculated with other methods (e.g. Zevenbergen & Thorne 1987). Then upslope curvature is calculated as the distance and flow proportional weighted average local curvature over a cell's upslope contributing area following the multiple flow direction algorithm after Freeman (1991). In a similar way the downslope curvature is calculated by summarizing the curvatures of all hydrologically downslope connected cells. The local upslope/downslope curvatures just take the immediately neighboured cells into account.

References

• Freeman, G.T. (1991): Calculating catchment area with divergent flow based on a regular grid. Computers and Geosciences, 17:413-22. ScienceDirect.
• Zevenbergen, L.W., Thorne, C.R. (1987): Quantitative analysis of land surface topography. Earth Surface Processes and Landforms, 12: 47-56. Wiley Online Library.

• Author: P.Gandelli, O.Conrad (c) 2015
• Menu: Terrain Analysis|Morphometry

Parameters

Command-line

Usage: saga_cmd ta_morphometry 26 [-DEM <str>] [-C_LOCAL <str>] [-C_UP <str>] [-C_UP_LOCAL <str>] [-C_DOWN <str>] [-C_DOWN_LOCAL <str>] [-WEIGHTING <double>]
  -DEM:<str>         	Elevation
	Grid, input
  -C_LOCAL:<str>     	Local Curvature
	Grid, output
  -C_UP:<str>        	Upslope Curvature
	Grid, output
  -C_UP_LOCAL:<str>  	Local Upslope Curvature
	Grid, output
  -C_DOWN:<str>      	Downslope Curvature
	Grid, output
  -C_DOWN_LOCAL:<str>	Local Downslope Curvature
	Grid, output
  -WEIGHTING:<double>	Upslope Weighting
	Floating point
	Minimum: 0.000000
	Maximum: 1.000000
	Default: 0.500000