[GRASS-user] Vector from Raster Problems (r.stream)

[Annalisa Minelli]

Yes, I found this problems too for using v.strahler..
so we tried to solve with r.strahler.. but we still have some problems for
low values of (r.wateshed) threshold..
but maybe Jarek has a better way with this new approach to the problem..
just "no dependencies" sounds good..
so we wait for good news!

Annalisa

2009/7/28 Jarek Jasiewicz <jarekj at amu.edu.pl>

>
>
> stephen sefick pisze:
>
>> I have compiled and used Jarek's stream order script and the results
>> look to be satisfactory- good job!.
>>
> You use windows as I remember, isn't it It is very important for me if
> program also work on windows. Please send me aslo feeback about time of
> analysis and size of maps
>
>>  I am having a hard time creating
>> vectors from this raster representation.  r.thin -> r.to.vect creates
>> lots of erroneous squares that I believe are there as an artifact of
>> the larger stream networks.
>>
> It is problem that no streams are marked as 0 (for now, it will be fixed to
> null). For now try to
> convert 0 to null with mapcalc formula: neworder=if(order=0,null(),order)
> and try again.
>
>>  The lower order (smaller) streams look
>> fine, but when you start getting to the higher order streams +5  I
>> think the r.thin algorithm may have problems delineating a stream.
>>
>
>  Is
>> there a way around this?  I would be happy with a line that ran
>> through the middle of the stream for now.  Some trick converting to
>> points and then to lines?  Or something along those lines.  Is there a
>> way to connect centroids?  I have made an area map of the streams
>> raster- can I connect the areas together?  Thanks for any help.
>> thanks,
>>
>>
>>
> I just work on another module which will be convert stream netowork to
> correct vector stream network (in most cases r.to.vect  do not it well) i
> thing it is metter of next week.
>
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