rsaga.wetness.index {RSAGA}R Documentation

SAGA Modules SAGA Wetness Index

Description

Calculate the SAGA Wetness Index (SWI), a modified topographic wetness index (TWI)

Usage

rsaga.wetness.index( in.dem, out.wetness.index, 
    out.carea, out.cslope, out.mod.carea, t.param, ...)

Arguments

in.dem input: digital elevation model (DEM) as SAGA grid file (default file extension: .sgrd)
out.wetness.index output (optional): wetness index grid. Existing files of the same name will be overwritten!
out.carea output (optional): catchment area
out.cslope output (optional): catchment slope
out.mod.carea output (optional): modified catchment area
t.param positive numeric value (optional): undocumented
... optional arguments to be passed to rsaga.geoprocessor, including the env RSAGA geoprocessing environment

Details

The SAGA Wetness Index is similar to the Topographic Wetness Index (TWI), but it is based on a modified catchment area calculation (out.mod.carea), which does not treat the flow as a thin film as done in the calculation of catchment areas in conventional algorithms. As a result, the SWI tends to assign a more realistic, higher potential soil wetness than the TWI to grid cells situated in valley floors with a small vertical distance to a channel.

Value

The type of object returned depends on the intern argument passed to the rsaga.geoprocessor. For intern=FALSE it is a numerical error code (0: success), or otherwise (default) a character vector with the module's console output.

Note

This function uses module 15 from the SAGA library ta_hydrology.

Author(s)

Alexander Brenning (R interface), Juergen Boehner and Olaf Conrad (SAGA module)

References

Boehner, J., Koethe, R. Conrad, O., Gross, J., Ringeler, A., Selige, T. (2002): Soil Regionalisation by Means of Terrain Analysis and Process Parameterisation. In: Micheli, E., Nachtergaele, F., Montanarella, L. (ed.): Soil Classification 2001. European Soil Bureau, Research Report No. 7, EUR 20398 EN, Luxembourg. pp.213-222.

See Also

rsaga.parallel.processing, rsaga.geoprocessor, rsaga.env

Examples

## Not run: 
# using SAGA grids:
rsaga.wetness.index("dem.sgrd","swi.sgrd")
## End(Not run)

[Package RSAGA version 0.9-5 Index]