NAME

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

SYNOPSIS

r.param.scale
r.param.scale help
r.param.scale [-c] in=string out=string [s_tol=float] [c_tol=float] [size=integer] [param=string] [exp=float] [zscale=float]

Flags:

-c
Constrain model through central window cell

Parameters:

in=string
Raster surface layer to process
out=string
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).

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: 2005/05/12 08:02:05 $


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