Hi Jarek!
I think that, with Horton and Strahler, it would be useful also Hack stream order, it is very nice because assigns value 1 to the main channel and so it is simple to achieve the main channel lenght. (Please see http://jgrass.wiki.software.bz.it/jgrass/Horton_Machine#head-f736e2e27c29fa8a71f227370b71a091fc03078f).
Cheers
margherita
Hi:
I do think it could be interesting, in fact I am using a couple of modules that performs Horton and Strahler ordering with my students. I just regret not be able to be more participative in this list.
I attach you the code in case it could be helpful.
The code it's a bit of a mess (not to mention that the comments are in Spanish 
It assumes that the tables linked to the vector data are in postgresql.
There are two modules:
v.ordena_red (network ordering), performs Strahler or Shreve ordering (crit parameter). "desembocadura" means outlet (you have to pass the cat value of the oulet reach).
v.str2hor converts an ordering from Horton to Strahler.
They work fine as long as your network nodes have only 3 links.
In case have any problem, you should delete all the created files and tables to rerun them.
Good luck.
Paco
Jarek Jasiewicz <jarekj@amu.edu.pl> escribió:
> Hi list!
>
> I've just thinked how to create horton stream order based on my > module strahler module and accumulation file. Hortons stream order > differs sligty form strahler order, see for example here fig. 1 page > 78 http://iahs.info/hsj/134/134008.pdf
>
> Because I have some tests results from some of you (many thanks for > your courage) i'm about to finish module, modify code to meet grass > requiments and officialy anouce it on grass-dev, but If I will add > horton stream order it will may take a bit more time.
>
> So I have 2 question about that (horton):
>
> Did you think taht horton stream order has already sense (it is > almost not in use)
>
> Does any body know any program (commercial or not) which calculate > horton's stream order
>
> Thanks for ansvers
> Jarek
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