SAGA 9.4.2 | Tool Library Documentation

Upslope and Downslope Curvature


Description

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


Parameters

 NameTypeIdentifierDescriptionConstraints
InputElevationgrid, inputDEM--
OutputLocal Curvaturegrid, outputC_LOCAL--
Upslope Curvaturegrid, outputC_UP--
Local Upslope Curvaturegrid, outputC_UP_LOCAL--
Downslope Curvaturegrid, outputC_DOWN--
Local Downslope Curvaturegrid, outputC_DOWN_LOCAL--
OptionsGrid Systemgrid systemPARAMETERS_GRID_SYSTEM--
Upslope Weightingfloating point numberWEIGHTING-Minimum: 0.000000 Maximum: 1.000000 Default: 0.500000

Command Line


Usage: saga_cmd ta_morphometry 26 [-DEM ] [-C_LOCAL ] [-C_UP ] [-C_UP_LOCAL ] [-C_DOWN ] [-C_DOWN_LOCAL ] [-WEIGHTING ]
  -DEM:         	Elevation
	grid, input
  -C_LOCAL:     	Local Curvature
	grid, output
  -C_UP:        	Upslope Curvature
	grid, output
  -C_UP_LOCAL:  	Local Upslope Curvature
	grid, output
  -C_DOWN:      	Downslope Curvature
	grid, output
  -C_DOWN_LOCAL:	Local Downslope Curvature
	grid, output
  -WEIGHTING:	Upslope Weighting
	floating point number
	Minimum: 0.000000
	Maximum: 1.000000
	Default: 0.500000