rsaga.local.morphometry {RSAGA}R Documentation

Local Morphometry

Description

Calculates local morphometric terrain attributes (i.e. slope, aspect and curvatures).

Usage

rsaga.local.morphometry(in.dem, out.slope, out.aspect, out.curv, 
    out.hcurv, out.vcurv, method = "poly2zevenbergen", ...)
rsaga.slope(in.dem, out.slope, method = "poly2zevenbergen", ...)
rsaga.aspect(in.dem, out.aspect, method = "poly2zevenbergen", ...)
rsaga.curvature(in.dem, out.curv, method = "poly2zevenbergen", ...)
rsaga.plan.curvature(in.dem, out.hcurv, method = "poly2zevenbergen", ...)
rsaga.profile.curvature(in.dem, out.vcurv, method = "poly2zevenbergen", ...)

Arguments

in.dem input: digital elevation model (DEM) as SAGA grid file (default file extension: .sgrd)
out.slope optional output: slope (in radian)
out.aspect optional output: aspect (in radian; north=0, clockwise angles)
out.curv optional output: curvature
out.hcurv optional output: horizontal curvature (plan curvature)
out.vcurv optional output: vertical curvature (profile curvature)
method character or numeric: algorithm (see References): Maximum Slope - Travis et al. (1975) ("maxslope", or 0), Max. Triangle Slope - Tarboton (1997) ("maxtriangleslope", or 1), Least Squares Fit Plane - Costa-Cabral and Burgess (1996) ("lsqfitplane", or 2), Fit 2nd Degree Polynomial - Bauer et al. (1985) ("poly2bauer", or 3), Fit 2nd Degree Polynomial - Heerdegen and Beran (1982) ("poly2heerdegen", or 4), default: Fit 2nd Degree Polynomial - Zevenbergen and Thorne (1987) ("poly2zevenbergen", or 5), Fit 3rd Degree Polynomial - Haralick (1983) ("poly3haralick", or 6).
... further arguments to rsaga.geoprocessor

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 the SAGA library ta_morphometry.

Author(s)

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

References

Maximum Slope: Travis, M.R., Elsner, G.H., Iverson, W.D., Johnson, C.G. (1975): VIEWIT: computation of seen areas, slope, and aspect for land-use planning. USDA F.S. Gen. Tech. Rep. PSW-11/1975, 70 p. Berkeley, California, U.S.A.

Maximum Triangle Slope: 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.

Least Squares or Best Fit Plane: Beasley, D.B., Huggins, L.F. (1982): ANSWERS: User's manual. U.S. EPA-905/9-82-001, Chicago, IL, 54 pp.

Costa-Cabral, M., Burges, S.J. (1994): Digital Elevation Model Networks (DEMON): a model of flow over hillslopes for computation of contributing and dispersal areas. Water Resources Research, 30(6): 1681-1692.

Fit 2nd Degree Polynomial: 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 zur Analyse von Agrar-Oekosystemen, eds.: Bork, H.-R., Rohdenburg, H., p. 1-15.

Heerdegen, R.G., Beran, M.A. (1982): Quantifying source areas through land surface curvature. Journal of Hydrology, 57.

Zevenbergen, L.W., Thorne, C.R. (1987): Quantitative analysis of land surface topography. Earth Surface Processes and Landforms, 12: 47-56.

Fit 3.Degree Polynom Haralick, R.M. (1983): Ridge and valley detection on digital images. Computer Vision, Graphics and Image Processing, 22(1): 28-38.

See Also

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

Examples

## Not run: 
# a simple slope algorithm:
rsaga.slope("lican.sgrd","slope","maxslope")
# same for ASCII grids (default extension .asc):
rsaga.esri.wrapper(rsaga.slope,in.dem="lican",out.slope="slope",method="maxslope")
## End(Not run)

[Package RSAGA version 0.9-6 Index]