rsaga.parallel.processing {RSAGA}R Documentation

Parallel Processing

Description

Calculate the size of the local catchment area (contributing area), the catchment height, catchment slope and aspect, and flow path length, using parallel processing algorithms including the recommended multiple flow direction algorithm. This set of algorithms processes a digital elevation model (DEM) downwards from the highest to the lowest cell.

Usage

rsaga.parallel.processing(in.dem, in.sinkroute, in.weight, 
    out.carea, out.cheight, out.cslope, out.caspect, out.flowpath, 
    step, method = "mfd", linear.threshold = Inf, 
    convergence = 1.1, ...)

Arguments

in.dem input: digital elevation model (DEM) as SAGA grid file (default file extension: .sgrd)
in.sinkroute optional input: SAGA grid with sink routes
in.weight optional intput: SAGA grid with weights
out.carea output: catchment area grid
out.cheight optional output: catchment height grid
out.cslope optional output: catchment slope grid
out.caspect optional output: catchment aspect grid
out.flowpath optional output: flow path length grid
step integer >=1: step parameter
method character or numeric: choice of processing algorithm: Deterministic 8 ("d8" or 0), Rho 8 ("rho8" or 1), Braunschweiger Reliefmodell ("braunschweig" or 2), Deterministic Infinity ("dinf" or 3), Multiple Flow Direction ("mfd" or 4, default).
linear.threshold numeric (number of grid cells): threshold above which linear flow (i.e. the Deterministic 8 algorithm) will be used; linear flow is disabled for linear.threshold=Inf (default)
convergence numeric >=0: a parameter for tuning convergent/ divergent flow; default value of 1.1 gives realistic results and should not be changed
... further arguments to rsaga.geoprocessor

Details

Refer to the references for details on the available algorithms.

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 0 from SAGA library ta_hydrology.

Author(s)

Alexander Brenning (R interface), Olaf Conrad (SAGA module)

References

Deterministic 8:

O'Callaghan, J.F., Mark, D.M. (1984): The extraction of drainage networks from digital elevation data. Computer Vision, Graphics and Image Processing, 28: 323-344.

Rho 8:

Fairfield, J., Leymarie, P. (1991): Drainage networks from grid digital elevation models. Water Resources Research, 27: 709-717.

Braunschweiger Reliefmodell:

Bauer, J., Rohdenburg, H., Bork, H.-R. (1985): Ein Digitales Reliefmodell als Vorraussetzung fuer ein deterministisches Modell der Wasser- und Stoff-Fluesse. Landschaftsgenese und Landschaftsoekologie, H. 10, Parameteraufbereitung fuer deterministische Gebiets-Wassermodelle, Grundlagenarbeiten zu Analyse von Agrar-Oekosystemen, eds.: Bork, H.-R., Rohdenburg, H., p. 1-15.

Deterministic Infinity:

Tarboton, D.G. (1997): A new method for the determination of flow directions and upslope areas in grid digital elevation models. Water Ressources Research, 33(2): 309-319.

Multiple Flow Direction:

Freeman, G.T. (1991): Calculating catchment area with divergent flow based on a regular grid. Computers and Geosciences, 17: 413-22.

Quinn, P.F., Beven, K.J., Chevallier, P., Planchon, O. (1991): The prediction of hillslope flow paths for distributed hydrological modelling using digital terrain models. Hydrological Processes, 5: 59-79.

See Also

rsaga.wetness.index, rsaga.geoprocessor, rsaga.env


[Package RSAGA version 0.9-6 Index]