[GRASS-user] calculation valley floor width in GRASS or some index indicating valley floor width?

[Helmut Kudrnovsky]

SBL wrote
> Hei Helumt,
> 
> In that case I would probably try r.param.scale in order to identify flat
> areas at maybe different scale levels.
> 
> V-valleys have a higher variation in aspect at the bottom (sides are
> almost facing each other and nearly "meet" at the lowest point in a
> V-valley). While sides are more or less steep. So slope and aspect at a
> coarser level (also available through r.param.scale) could help to
> distinguish V- and U-valleys.
> 
> Depending on scale U-Valleys have a TPI of ~0 at the bottom and ~0 at the
> middle of the sides (equaly much terrain above and below a focal cell in
> the given neighborhood).
> 
> Some background material on TPI can be found here:
> http://www.jennessent.com/arcview/tpi.htm 
> Jenness used ArcView. Yet TPI is a simple combination of r.neighbors and a
> mapcalc.
> 
> Good luck with your modelling.


as a possible additional parameter for such a modelling, I've tried to
implement a Multi-resolution Valley Bottom Flatness (MrVBF) index.

http://lists.osgeo.org/pipermail/grass-commit/2014-June/031834.html

Author: hellik
Date: 2014-06-22 16:04:15 -0700 (Sun, 22 Jun 2014)
New Revision: 60919

Added:
   grass-addons/grass7/raster/r.valley.bottom/
   grass-addons/grass7/raster/r.valley.bottom/Makefile
   grass-addons/grass7/raster/r.valley.bottom/r.valley.bottom.html
   grass-addons/grass7/raster/r.valley.bottom/r.valley.bottom.py
Log:
r.valley.bottom: a script to calculate a Multi-resolution Valley Bottom
Flatness (MrVBF) index 

testing and hints for improvement are very welcome.

thanks



-----
best regards
Helmut
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