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

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)"