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NAME

r.param.scale - Extracts terrain parameters from a DEM.
Uses a multi-scale approach by taking fitting quadratic parameters to any size window (via least squares).

KEYWORDS

raster, geomorphology

SYNOPSIS

r.param.scale
r.param.scale help
r.param.scale [-c] input=name output=name [s_tol=float] [c_tol=float] [size=integer] [param=string] [exp=float] [zscale=float] [--overwrite] [--verbose] [--quiet]

Flags:

-c
Constrain model through central window cell
--overwrite
Allow output files to overwrite existing files
--verbose
Verbose module output
--quiet
Quiet module output

Parameters:

input=name
Name of input raster map
output=name
Output raster layer containing morphometric parameter
s_tol=float
Slope tolerance that defines a 'flat' surface (degrees)
Default: 1.0
c_tol=float
Curvature tolerance that defines 'planar' surface
Default: 0.0001
size=integer
Size of processing window (odd number only, max: 69)
Default: 3
param=string
Morphometric parameter in 'size' window to calculate
Options: elev,slope,aspect,profc,planc,longc,crosc,minic,maxic,feature
Default: elev
exp=float
Exponent for distance weighting (0.0-4.0)
Default: 0.0
zscale=float
Vertical scaling factor
Default: 1.0

DESCRIPTION

r.param.scale extracts terrain parameters from a DEM. Uses a multi-scale approach by fitting a bivariate quadratic polynomial to a given window size using least squares.

The module calculates the following parameters (terminology is from Wood, 1996 with related terminology used in other GRASS modules listed in brackets):

NOTES

In r.param.scale the direction of maximum gradient (considered downslope) is stored as (West is 0 degree, East is +/- 180 degree): Note that the aspect map is calculated differently from r.slope.aspect.

Still to do

Fix bug when `constrain through central cell' option selected. Create color tables for all output files (presently only on features).

EXAMPLE

The next commands will create a geomorphological map of the Spearfish region:
g.region rast=elevation.10m -p
r.param.scale in=elevation.10m output=morphology param=feature size=9
d.mon x0
d.rast.leg morphology

r.param.scale generated geomorphological map
Geomorphological map of a subregion in the Spearfish (SD) area

SEE ALSO

Java Code in LandSerf that implements the same procedure

REFERENCE

Wood, J. (1996): The Geomorphological characterisation of Digital Elevation Models. Diss., Department of Geography, University of Leicester, U.K.
online at:
http://www.soi.city.ac.uk/~jwo/phd/

AUTHOR

jwo@le.ac.uk - ASSIST's home

Update to FP 3/2002: L. Potrich, M. Neteler, S. Menegon (ITC-irst)

Last changed: $Date: 2009-04-02 23:17:56 -0800 (Thu, 02 Apr 2009) $


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