r.param.scale

NAME

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

Usage:

r.param.scale [-c] in=name out=name [s_tol=value] [c_tol=value] [size=value] [param=name] [exp=value] [zscale=value]

Flags:

-c Constrain model through central window cell

Parameters:

in Raster surface layer to process

out Output raster layer containing morphometric parameter

s_tol Slope tolerance that defines a `flat' surface (degrees)
default: 1.0

c_tol Curvature tolerance that defines `planar' surface
default: 1.0

size Size of processing window (odd number only)
default: 3

param Morphometric parameter to calculate
options: elev,slope,aspect,profc,planc,longc,crosc,minic,maxic, feature
default: elev

exp Exponent for distance weighting (0.0-4.0)
default: 0.0

zscale Vertical scaling factor
default: 1.0

r.param.scale can calculate the following:

elev: Generalised elevation value.

slope: Maximum gradient at a point.

aspect: Direction of maximum gradient.

profc: Profile convexity (vertical in direction of steepest slope).

planc: Plan convexity (contour curvature).

crosc: Cross sectional convexity (tangent to contours, downslope).

longc: Longitudinal convexity (perpendicular to contours downslope).

minic: Minimum convexity.

maxic: Maximum convexity.

features: Morphometric features:
peaks, ridges, passes, channels, pits and planes.

HISTORY

Modified to include constrained fitting. 
Jo Wood, April, 1995 
-------
Modified to include weighting matrix and double precision arithmetic.
Jo Wood, 9th May, 1995.
-------
Modified to include two separate tolerance values for feature detection.
Jo Wood, 23rd May, 1995.

Still to do

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

REFERENCE

Wood, J. (1996): The Geomorphological characterisation of Digital Elevation Models. Diss., Department of Geography, University of Leicester, U.K.
online at:
www.geog.le.ac.uk/jwo/research/dem_char/thesis/index.html