SAGA 9.4.2 | Tool Library Documentation

Topographic Wetness Index (One Step)


Description

Calculates the Topographic Wetness Index (TWI) based on the supplied Digital Elevation Model (DEM). Slopes (Beta), Specific Catchment Areas (SCA), and a depressionless DEM for SCA calculation are derived internally. TWI = ln(SCA / tan(Beta))


References


Parameters

 NameTypeIdentifierDescriptionConstraints
InputElevationgrid, inputDEM--
OutputTopographic Wetness Indexgrid, outputTWI--
OptionsGrid Systemgrid systemGRID_SYSTEM--
Flow DistributionchoiceFLOW_METHOD-Available Choices: [0] Deterministic 8 [1] Rho 8 [2] Braunschweiger Reliefmodell [3] Deterministic Infinity [4] Multiple Flow Direction [5] Multiple Triangular Flow Direction [6] Multiple Maximum Downslope Gradient Based Flow Direction Default: 0

Command Line


Usage: saga_cmd ta_hydrology twi [-DEM ] [-TWI ] [-FLOW_METHOD ]
  -DEM:        	Elevation
	grid, input
  -TWI:        	Topographic Wetness Index
	grid, output
  -FLOW_METHOD:	Flow Distribution
	choice
	Available Choices:
	[0] Deterministic 8
	[1] Rho 8
	[2] Braunschweiger Reliefmodell
	[3] Deterministic Infinity
	[4] Multiple Flow Direction
	[5] Multiple Triangular Flow Direction
	[6] Multiple Maximum Downslope Gradient Based Flow Direction
	Default: 0