[GRASS-user] Building topologically correct stream network

[Margherita Di Leo]

I'm sorry but the procedure that I proposed does not produce good 
results. In fact the ascii file produced by v.strahler has very strange 
orders, and also many 0 (that does not have sense in strahler order!). I 
think the problem is generated in finding the outlets and/or confluences.
Waiting for the response of the List (please)..

margherita


Jarek Jasiewicz wrote:
> Hi
>
> maybe this will help:
>
> http://gis.vsb.cz/GIS_Ostrava/GIS_Ova_2009/sbornik/Lists/Papers/060.pdf
>
> it require another gis program but gives great results!
>
> Jarek
>
>
> Margherita Di Leo pisze:
>> Hi Stephen,
>> I actually am fighting against almost the same problem, so let's do 
>> it together :)
>> I found that r.strahler.sh works well to delineate streams and 
>> correct topology, (I use a treshold of 1km^2, it works well but don't 
>> ask me why :) ), but (in my little experience) does not work to order 
>> streams, so I must run v.strahler after r.strahler.sh.
>> I know it's a very small hint but hope this helps.
>>
>> Best
>> margherita
>>
>>
>> I have a low relief area in the costal plain of georgia that I am 
>> trying to produce a topologically correct stream network. There are 
>> many breaks in the flow accumulation grid and I would like to 
>> delineate the streams and "correct" the topology after r.thin and 
>> r.to.vect have been preformed so that I can then use v.strahler to 
>> order the streams. Thanks for any help and I will provide and data 
>> that would be helpful. thanks,
>>
>>
>> -- Stephen Sefick Let's not spend our time and resources thinking 
>> about things that are so little or so large that all they really do 
>> for us is puff us up and make us feel like gods. We are mammals, and 
>> have not exhausted the annoying little problems of being mammals. -K. 
>> Mullis
>>
>


-- 
Eng. Margherita Di Leo
Ph.D. Student 
Methods and Technologies for Environmental Monitoring
Department of Environmental Engineering and Physics (DIFA)

University of Basilicata 
Campus Macchia Romana
85100 - Potenza 
Italy

Office: +39-0971205363
Fax: +39-0971205160
E-mail: dileomargherita AT gmail DOT com
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