Re: [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 > 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 
mailto:kattwinkel-m...@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
>>
>> ___
>> grass-user mailing list
>> grass-user@lists.osgeo.org 
>> https://lists.osgeo.org/mailman/listinfo/grass-user
>
>
>
>
> --
> 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@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

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

[Markus Metz]

On Wed, Jul 11, 2018 at 3:55 AM, Huidae Cho  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-m...@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
>>
>> ___
>> grass-user mailing list
>> grass-user@lists.osgeo.org
>> https://lists.osgeo.org/mailman/listinfo/grass-user
>
>
>
>
> --
> 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@lists.osgeo.org
> https://lists.osgeo.org/mailman/listinfo/grass-user
___
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Re: [GRASS-user] limit number of confluent streams in r.steam.extract or r.watershed

[Huidae Cho]

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.

Regards,
Huidae


On Thu, Jul 5, 2018 at 6:40 AM, Mira Kattwinkel <
kattwinkel-m...@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
>
> ___
> grass-user mailing list
> grass-user@lists.osgeo.org
> https://lists.osgeo.org/mailman/listinfo/grass-user




-- 
Huidae Cho, Ph.D., PE, M.ASCE, CFM, GISP
Senior Geospatial Engineer, MapAnything
Open Source GIS Developer, GRASS GIS Development Team
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