Huidae Cho 32085694d6 Fix links %!s(int64=8) %!d(string=hai) anos
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Makefile d6700ffb2c Update LIBES, DEPENDENCIES from linkage database %!s(int64=15) %!d(string=hai) anos
README db49180dd7 welcome to GRASS 7.0.svn %!s(int64=17) %!d(string=hai) anos
arc.to.gridatb.pl 7da91113a6 rename perl scripts to make it more obvious what they are (merge from devbr6) %!s(int64=13) %!d(string=hai) anos
file_io.c 7a89c7d27d parameter descriptions updated; routine names changed %!s(int64=11) %!d(string=hai) anos
global.h ba3050fee3 Easy-to-read macro names %!s(int64=11) %!d(string=hai) anos
gridatb.to.arc.pl 7da91113a6 rename perl scripts to make it more obvious what they are (merge from devbr6) %!s(int64=13) %!d(string=hai) anos
main.c eccf07b124 add various keywords to modules %!s(int64=9) %!d(string=hai) anos
r.topidx.html 32085694d6 Fix links %!s(int64=8) %!d(string=hai) anos
topidx.c 822f70d04b r.topidx: indent %!s(int64=9) %!d(string=hai) anos

README

Main algorithm sources are rewritten from GRIDATB.FOR.
GRIDATB.FOR is available from http://www.es.lancs.ac.uk/hfdg/topmodel.html.

Thanks to Keith Beven.



[r.topidx]
creates topographic index, ln(a/tan(beta)), map from elevation map.

where
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)


Elevation map need not to be rectangular if study basin was already determined.
Non-interesting region may have NULL values. Study basin map can be taken
from r.water.outlet then the following r.mapcalc statements will create
study basin extracted elevation map.

r.mapcalc "belev = if(isnull(basin), basin, elev)"