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<p>Thank you for your help,</p>
<p>i'll try r.stream.extract</p>
<p>I do have set a small threshold value but it is on purpose.<br>
The streams i am trying to model are not hydrological.</p>
<p>Best regards,</p>
<p>Adrien<br>
</p>
<div class="moz-cite-prefix">Le 19-03-31 à 09 h 48, Markus Metz a
écrit :<br>
</div>
<blockquote type="cite"
cite="mid:CAG+h=FHVqqeouDQEH8eaSh1dSo6GP11MVNBsgHejen3YhfTV+A@mail.gmail.com">
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<br>
On Sat, Mar 30, 2019 at 5:30 PM Micha Silver <<a
href="mailto:tsvibar@gmail.com" moz-do-not-send="true">tsvibar@gmail.com</a>>
wrote:<br>
><br>
><br>
> On 29/03/2019 22:03, Adrien André wrote:<br>
><br>
> Hello,<br>
><br>
> following the wiki doc about stream extraction [1], once
the stream layer thinned and vectorized,<br>
> there are many small arcs i would like to remove (see
attached capture [2]).<br>
><br>
> So, with the underlying drainage direction map [3], and the
resolution r, i would like to delete segments<br>
> - about r*sqrt(2) long<br>
> - whose azimuth is more than 45° different from the pixel
value under its starting point.<br>
><br>
><br>
> This might be possible, but I think the best approach would
be to choose the correct threshold value for r.watershed from
the start.<br>
><br>
> Trying to manually "fiddle" with the stream network will
most likely leave you with disconnected segments, or other
inconsistencies.<br>
<div><br>
</div>
<div>+1</div>
<div><br>
</div>
<div>Please try r.stream.extract in order to get a clean vector
stream network. The approach r.thin + r.to.vect creates noise
and does not always follow flow directions.</div>
<div><br>
</div>
<div>Markus M</div>
<div><br>
</div>
<div>></div>
><br>
> But i still haven't figured a way to achieve this.<br>
><br>
> Do you have any advice ?<br>
><br>
> Thank you,<br>
><br>
> Best regards,<br>
><br>
> [1] <a
href="https://grasswiki.osgeo.org/wiki/Creating_watersheds#Display_first_results"
moz-do-not-send="true">https://grasswiki.osgeo.org/wiki/Creating_watersheds#Display_first_results</a><br>
> [2] <a
href="https://framapic.org/1exdxrdqxemw/ytuVxiBp2FKh.png"
moz-do-not-send="true">https://framapic.org/1exdxrdqxemw/ytuVxiBp2FKh.png</a><br>
> [3] <a
href="https://grass.osgeo.org/grass74/manuals/r.watershed.html"
moz-do-not-send="true">https://grass.osgeo.org/grass74/manuals/r.watershed.html</a><br>
><br>
><br>
> _______________________________________________<br>
> grass-user mailing list<br>
> <a href="mailto:grass-user@lists.osgeo.org"
moz-do-not-send="true">grass-user@lists.osgeo.org</a><br>
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href="https://lists.osgeo.org/mailman/listinfo/grass-user"
moz-do-not-send="true">https://lists.osgeo.org/mailman/listinfo/grass-user</a><br>
><br>
> -- <br>
> Micha Silver<br>
> Ben Gurion Univ.<br>
> Sde Boker, Remote Sensing Lab<br>
> cell: +972-523-665918<br>
><br>
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</blockquote>
<pre class="moz-signature" cols="72">--
Adrien</pre>
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