[GRASS-user] Snapping river segments

[Jarek Jasiewicz]

Colin Nielsen napisał(a):
> With over to 10,000 river segments that isn't exactly a practical
> solution for me. Anything else?
>
> On 3/22/07, Jarek Jasiewicz <jarekj at amu.edu.pl> wrote:
>> Colin Nielsen napisa�(a):
>> > I'm trying to extract only the largest rivers from a very detailed
>> > hydrology map (mostly for display purposes). Right now the map just
>> > looks black with lines. I've managed to use v.extract for areas but
>> > since the rivers are in segments i can't use v.extract for lengths.
>> > I've tried v.clean snap but it doesn't seem to be doing what I want it
>> > to. Any advice?
>> >
>> > -Colin
>> >
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>> for now (with my previous experiences with exactly the same problem)
>> v.digit seems to be the fastest solution :(
>>
have you some addational atributies on segment?
It is digitised map (it produced a segment between every juncion) 
without categories and another atributies?

If so, there is no solution in grass (IMHO), but you can search solution 
in JGRASS in tool called horton machine it seems it will help you, also 
look for solution in TAS (Terrain analisys system WINDOWS only, free 
strahler analisys) or maybe the best fot this TauDEM free extension for 
ArcGIS (not free) and Mapwindow (free), but I don't guarantee success.


or it is regulral hydrological map with adational attributies if so 
there shall be some addational atributies like hydrological id or name, 
SQL shall help
cherrs
Jarek