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)"
r.avgstats prints out averaged statistics for topographic index.
Flags:
- -o
- Overwrite output map
- -v
- Output verbosely
Parameters:
- input
- Elevation map
- output
- Topographic index ln(a/tanB) map
SEE ALSO
r.topmodel
AUTHORS
Main algorithm sources are rewritten from GRIDATB.FOR.
GRIDATB.FOR is available from
www.es.lancs.ac.uk/hfdg/topmodel.html.
Thanks to Keith Beven.
GRASS port by Huidae Cho
Hydro Laboratory, Kyungpook National University, South Korea