[GRASS-user] limit number of confluent streams in r.steam.extract or r.watershed

[Mira Kattwinkel]

Dear Markus,

thanks for your advice. You are right, the best thing would be to 
enhance the statistical package.

No, it is not about major streams only but the method is just 
implemented in a way that it can only deal with two confluences at one 
point.

All the best,

Mira


On 11/07/18 22:01, Markus Metz wrote:
>
>
> On Wed, Jul 11, 2018 at 3:55 AM, Huidae Cho <grass4u at gmail.com 
> <mailto:grass4u at gmail.com>> wrote:
> >
> > Hello,
> >
> > Not sure if I understood your question. Are you trying to extract 
> major streams only? r.stream.extract already returns a valid stream 
> network with confluences snapped to the main stem. Also, limiting the 
> number of confluent streams and moving (?) streams at the confluences 
> are two different tasks, I believe. Maybe, you need to be more 
> specific with some examples.
>
> Limiting the number of confluent streams would conflict with both the 
> method to determine flow directions and the method to extract streams. 
> Moving streams at confluences a tiny little bit is IMHO a custom 
> post-processing step.
>
> I would rather suggest to enhance the R package SSN such that it can 
> deal with more than two streams joining at a confluence. But maybe SSN 
> is meant to work with major streams only, in which case the threshold 
> to extract streams would need to be increased.
>
> Markus M
>
> >
> > Regards,
> > Huidae
> >
> >
> > On Thu, Jul 5, 2018 at 6:40 AM, Mira Kattwinkel 
> <kattwinkel-mira at uni-landau.de <mailto:kattwinkel-mira at uni-landau.de>> 
> wrote:
> >>
> >> Dear list,
> >>
> >> is there any way to limit the number of confluent streams in 
> r.stream.extract or r.watershed?
> >>
> >> I am working with statistical models (R package SSN) that can only 
> deal with such dichotomous networks. Currently, I am developing a 
> method to move streams a tiny bit at the confluences to get a valid 
> network, but I wonder if something like this already exists. That 
> would make my life much easier.
> >>
> >> All the best,
> >>
> >> Mira
> >>
> >> ---
> >>
> >> Dr. Mira Kattwinkel
> >> Quantitative Landscape Ecology
> >> Institute for Environmental Sciences
> >> University of Koblenz-Landau
> >> Fortstraße 7
> >> 76829 Landau
> >> Germany
> >> Phone: + 49 6341 280-31553
> >> Office: Building I, Room 2.02
> >>
> >> _______________________________________________
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> >
> >
> >
> >
> > --
> > Huidae Cho, Ph.D., PE, M.ASCE, CFM, GISP
> > Senior Geospatial Engineer, MapAnything
> > Open Source GIS Developer, GRASS GIS Development Team
> >
> > _______________________________________________
> > grass-user mailing list
> > grass-user at lists.osgeo.org <mailto:grass-user at lists.osgeo.org>
> > https://lists.osgeo.org/mailman/listinfo/grass-user
>

-- 
Dr. Mira Kattwinkel
Quantitative Landscape Ecology
Institute for Environmental Sciences
University of Koblenz-Landau
Fortstraße 7
76829 Landau
Germany
Phone: + 49 6341 280-31553
Office: Building I, Room 2.02