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r.topidx
Langue: en
Version: 371631 (fedora - 01/12/10)
Section: 1 (Commandes utilisateur)
NAME
r.topidx - Creates topographic index [ln(a/tan(beta))] map from elevation map.KEYWORDS
rasterSYNOPSIS
r.topidxr.topidx help
r.topidx input=name output=name [--overwrite] [--verbose] [--quiet]
Flags:
- --overwrite
Allow output files to overwrite existing files- --verbose
Verbose module output- --quiet
Quiet module output
Parameters:
- input=name
Input elevation map- output=name
Output topographic index map
DESCRIPTION
r.topidx creates topographic index (wetness index), ln(a/tan(beta)), map from elevation mapwhere
a: the area of the hillslope per unit contour length that drains through any point,
tan(beta): the local surface topographic slope (delta vertical) / (delta horizontal).
Input maps may have NULL values. For example, if you have a MASK for a watershed (basin map from r.water.outlet), the following command will create a masked elevation map (belev):
r.mapcalc "belev = if(isnull(basin), basin, elev)"
r.stats -Anc prints out averaged statistics for topographic index.
SEE ALSO
r.topmodel, r.water.outlet, r.mapcalcREFERENCE
Moore, I.D., R.B. Grayson, and A.R. Ladson, 1991. Digital terrain modeling: A review of hydrological, geomorphological, and biological applications. Hydrol. Processes 5:3-30.AUTHORS
Main algorithm sources are rewritten from GRIDATB.FOR.Thanks to Keith Beven.
GRASS port by Huidae Cho
Hydro Laboratory, Kyungpook National University, South Korea
Last changed: $Date: 2007-01-17 17:35:29 +0100 (Wed, 17 Jan 2007) $
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