Tool 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
- Menu: Terrain Analysis|Hydrology|Topographic Indices
Parameters
| Name | Type | Identifier | Description | Constraints |
Input | Slope | Grid, input | SLOPE | - | - |
Catchment Area | Grid, input | AREA | - | - |
Transmissivity (*) | Grid, input, optional | TRANS | - | - |
Output | Topographic Wetness Index | Grid, output | TWI | - | - |
Options | Grid System | Grid system | PARAMETERS_GRID_SYSTEM | - | - |
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, input, optional
-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