NAME
r.roughness.window.vector - Calculates surface roughness in a moving-window, as the orientation of vectors normal to surface planes.
KEYWORDS
raster, elevation, slope, aspect
SYNOPSIS
r.roughness.window.vector
r.roughness.window.vector help
r.roughness.window.vector map=string
[slope=string] [aspect=string]
[window=integer] [strength=string]
[fisher=string] [compass=string]
[colatitude=string] [xcos=string] [ycos=string] [zcos=string] [--overwrite] [--verbose] [--quiet]
Flags:
- --overwrite
- Allow output files to overwrite existing files
- --verbose
- Verbose module output
- --quiet
- Quiet module output
Parameters:
- map=string
- Input elevation raster map
- slope=string
- Input slope map
- aspect=integer
- Input aspect map
- window=integer
- Moving-window size (uses r.neighbors)
- strength=string (optional)
- Output "vector strength" map
- fisher=string (optional)
- Output "Fisher's K parameter" map
- compass=string (optional)
- Input compass aspect map
- colatitude=string (optional)
- Input colatitude map
- xcos=string (optional)
- Input x directional cosine map
- ycos=string (optional)
- Input y directional cosine map
- zcos=string (optional)
- Input z directional cosine map
DESCRIPTION
In this script surface roughness is taken as the dispersion of vectors
normal to surface areas (pixels). Normal vectors are defined by
slope and aspect.
This script will create several temporary
maps, for the directional cosines in each direction (x,y,z), for the
sum of these cosines and vector strengh.
The options compass, colatitude, xcos, ycosm and zcos
are created as temporary files each time the script is run. If the user
wants to create several map (with different window sizes, for
instance), it is recommended to create those maps with r.mapcalc and use them as input:
r.mapcalc compass = "if(aspect==0,0,if(aspect < 90, 90-aspect, 360+90-aspect))"
r.mapcalc colatitude = "90 - slope"
r.mapcalc xcos = "sin(colatitude)*cos(compass)"
r.mapcalc ycos = "sin(colatitude)*sin(compass)"
r.mapcalc zcos = "cos(colatitude)"
If the user does not specify the output maps names, they will be set to
INPUT_MAP_vector_strength_NxN
and
INPUT_MAP_fisher_K_NxN
where N is the window size.
REFERENCES
Hobson, R.D., 1972. Surface roughness in topography: quantitative approach. In: Chorley, R.J. (ed) Spatial analysis in geomorphology. Methuer, London, p.225-245.
McKean, J. & Roering, J., 2004. Objective landslide detection and surface morphology mapping using high-resolution airborne laser altimetry. Geomorphology, 57:331-351
AUTHOR
Carlos Henrique Grohmann
Institute of Geosciences, University of São Paulo, Brazil.
Last changed: $Date$
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