Luca Delucchi 021fa9d879 r.topidx: added examples and figures, thanks to Jerry Huang and Google Code-in 7 gadi atpakaļ
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Makefile d6700ffb2c Update LIBES, DEPENDENCIES from linkage database 16 gadi atpakaļ
README db49180dd7 welcome to GRASS 7.0.svn 17 gadi atpakaļ
arc.to.gridatb.pl 7da91113a6 rename perl scripts to make it more obvious what they are (merge from devbr6) 13 gadi atpakaļ
file_io.c 7a89c7d27d parameter descriptions updated; routine names changed 11 gadi atpakaļ
global.h ba3050fee3 Easy-to-read macro names 11 gadi atpakaļ
gridatb.to.arc.pl 7da91113a6 rename perl scripts to make it more obvious what they are (merge from devbr6) 13 gadi atpakaļ
main.c 3fc9d69249 r.watershed, r.topidx: more keywords 8 gadi atpakaļ
r.topidx.html 021fa9d879 r.topidx: added examples and figures, thanks to Jerry Huang and Google Code-in 7 gadi atpakaļ
r_topidx.png 021fa9d879 r.topidx: added examples and figures, thanks to Jerry Huang and Google Code-in 7 gadi atpakaļ
topidx.c 822f70d04b r.topidx: indent 10 gadi atpakaļ

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)"