Module Topographic Wetness Index (TWI)
Calculation of the slope and specific catchment area (SCA) based Topographic Wetness Index (TWI)
References:
Beven, K.J., Kirkby, M.J. (1979):
A physically-based variable contributing area model of basin hydrology'
Hydrology Science Bulletin 24(1), p.43-69
Boehner, J., Selige, T. (2006):
Spatial Prediction of Soil Attributes Using Terrain Analysis and Climate Regionalisation'
In: Boehner, J., McCloy, K.R., Strobl, J.: 'SAGA - Analysis and Modelling Applications', Goettinger Geographische Abhandlungen, Vol.115, p.13-27
Moore, I.D., Grayson, R.B., Ladson, A.R. (1991):
'Digital terrain modelling: a review of hydrogical, geomorphological, and biological applications'
Hydrological Processes, Vol.5, No.1
- Author: O.Conrad (c) 2003
- Specification: grid
- Menu: Terrain Analysis|Hydrology|Topographic Indices
Parameters
| | Name | Type | Identifier | Description | Constraints |
|---|
| Input | Slope | Grid (input) | SLOPE | - | - |
| Catchment Area | Grid (input) | AREA | - | - |
| Transmissivity (*) | Grid (optional input) | TRANS | - | - |
| Output | Topographic Wetness Index | Grid (output) | TWI | - | - |
| Options | Area Conversion | Choice | CONV | - | Available Choices:
[0] no conversion (areas already given as specific catchment area)
[1] 1 / cell size (pseudo specific catchment area)
Default: 0 |
| Method (TWI) | Choice | METHOD | - | Available Choices:
[0] Standard
[1] TOPMODEL
Default: 0 |
| (*) optional |
Command-line
Usage: saga_cmd ta_hydrology 20 [-SLOPE <str>] [-AREA <str>] [-TRANS <str>] [-TWI <str>] [-CONV <str>] [-METHOD <str>]
-SLOPE:<str> Slope
Grid (input)
-AREA:<str> Catchment Area
Grid (input)
-TRANS:<str> Transmissivity
Grid (optional input)
-TWI:<str> Topographic Wetness Index
Grid (output)
-CONV:<str> Area Conversion
Choice
Available Choices:
[0] no conversion (areas already given as specific catchment area)
[1] 1 / cell size (pseudo specific catchment area)
Default: 0
-METHOD:<str> Method (TWI)
Choice
Available Choices:
[0] Standard
[1] TOPMODEL
Default: 0