Note: This document is for an older version of GRASS GIS that will be discontinued soon. You should upgrade, and read the current manual page.
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
INPUT_MAP_fisher_K_NxN
# calculate roughness factor by search window = 5 r.roughness.vector elevation=DEM slope=slope aspect=aspect window=5
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.
https://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.
https://doi.org/10.1109/TGRS.2010.2053546
Available at: r.roughness.vector source code (history)
Latest change: Tuesday Nov 05 09:35:47 2024 in commit: f00067506253c89598cffadc3c7fa07cff7233fd
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