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<div class="moz-cite-prefix">Thanks Tom,<br>
this is what I meant by looping over each subbasin, but that is
exactly what I would like to avoid as it would take a lot of time
for 1000+ subbasins and I dont really need all the other analysis.<br>
<br>
Cheers,<br>
Michel<br>
<br>
On 02/16/2014 05:58 PM, Thomas Adams wrote:<br>
</div>
<blockquote
cite="mid:CAGxgkWhz0pFnWJ4BFeRnO4H_UAwFc-yRdgkVQVgmWkfLhjun6Q@mail.gmail.com"
type="cite">
<div dir="ltr">Michel,
<div><br>
</div>
<div>If you do what you suggest, but first apply a MASK using
each subbasin; so, when you calculate the statistics, they
will be for one subbasin at a time; with a very simple script
you could loop through each subbasin.</div>
<div><br>
</div>
<div>I hope this helps.</div>
<div><br>
</div>
<div>Cheers!</div>
<div>Tom</div>
<div class="gmail_extra"><br>
<br>
<div class="gmail_quote">On Sun, Feb 16, 2014 at 11:07 AM,
Michel Wortmann <span dir="ltr"><<a
moz-do-not-send="true"
href="mailto:wortmann@pik-potsdam.de" target="_blank">wortmann@pik-potsdam.de</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">Hi list,<br>
I'm looking for a way to calculate the main channel length
and width for a large number of subbasins within a river
basin. I understand that the r.stream.* addon / R.basin
gives me the main channel length along with a tone of
other statistics but only for one catchment. Of course, I
could loop over all my subbasins and calculate the
statistics one by one, but I fear that will be time
consuming and I dont actually need all the other analysis.<br>
<br>
I have got an efficient way to calculate the mainstream
for each subbasin as a vector, but I'm struggling to get
from there to the distance of the longest segment in each
subbasin. Maybe someone has an idea to complete this idea
of a work flow:<br>
<br>
raster=mainstreams (thinned raster with unique categories
for each subbasin)<br>
<br>
r.to.vect to vectorise, this unfortunately gives me line
segments crossing over subbasin boundaries<br>
<br>
somehow make stream segments from each subbasin<br>
<br>
v.to.db to measure the distance of each line segment<br>
<br>
choose the longest distance for each subbasin<br>
<br>
<br>
Any suggestions/help would be much appreciated.<br>
Regards,<br>
Michel<br>
<br>
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</blockquote>
</div>
<br>
<br>
</div>
</div>
</blockquote>
<br>
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