r.roughness.vector - GRASS GIS manual

NAME

r.roughness.vector - Calculates surface roughness in a moving-window, as the orientation of vectors normal to surface planes.

KEYWORDS

raster, terrain, aspect, slope, roughness

SYNOPSIS

r.roughness.vector

r.roughness.vector --help

r.roughness.vector elevation=name slope=string aspect=string [window=integer] [strength=string] [fisher=string] [compass=string] [colatitude=string] [xcos=string] [ycos=string] [zcos=string] [--help] [--verbose] [--quiet] [--ui]

Flags:

--help: Print usage summary
--verbose: Verbose module output
--quiet: Quiet module output
--ui: Force launching GUI dialog

Parameters:

elevation=name [required]: Name of elevation raster map
slope=string [required]: Input slope map
aspect=string [required]: Input aspect map
window=integer: Moving-window size (uses r.neighbors); Default: 3
strength=string: Output "vector strength" map
fisher=string: Output "Fisher's K parameter" map
compass=string: Input compass aspect map (optional)
colatitude=string: Input colatitude map (optional)
xcos=string: Input x directional cosine map (optional)
ycos=string: Input y directional cosine map (optional)
zcos=string: Input z directional cosine map (optional)

DESCRIPTION
EXAMPLE
SEE ALSO
REFERENCES
AUTHORS

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 strength.

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.

EXAMPLE

  # calculate roughness factor by search window = 5
  r.roughness.vector elevation=DEM slope=slope aspect=aspect window=5

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. http://dx.doi.org/10.1016/S0169-555X(03)00164-8.

Grohmann, C.H., Smith, M.J. & Riccomini, C., 2011. Multiscale Analysis of Topographic Surface Roughness in the Midland Valley, Scotland. Geoscience and Remote Sensing, IEEE Transactions on, 49:1200-1213. http://dx.doi.org/10.1109/TGRS.2010.2053546

AUTHORS

Carlos Henrique Grohmann - Institute of Energy and Environment, University of São Paulo, Brazil. (http://carlosgrohmann.com)
Helmut Kudrnovsky

SOURCE CODE

Available at: r.roughness.vector source code (history)