<div dir="ltr"><div><div>I think you must use the accumulation map in the r.distance command. But bear in mind that you don't need the accumulation map but only your drainedge lines. Thus, you can threshold the flow accum map in order to delineate the rivers. And that could be a bit smaller than your complete flow accumulation map.<br><br></div>Cheers<br></div>Daneil<br></div><br><div class="gmail_quote"><div dir="ltr">On Wed, Mar 29, 2017 at 1:24 PM Ang Sherpa <<a href="mailto:angsherpa232@gmail.com">angsherpa232@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr" class="gmail_msg">Thanks Daniel, <div class="gmail_msg"><br class="gmail_msg"><div class="gmail_msg">Since I am developing Grass Gis based interactive app to delineate watershed basin, I have to bundle those raster files along with other python packages. When the users installs the app, these files will be automatically copied and ready to use for "r.water.outlet" module through python script i.e. users just have to enter coordinate in the GUI.There will be just a single pair of coordinate at a time. </div></div><div class="gmail_msg"><br class="gmail_msg"></div><div class="gmail_msg">My concern is that whether drainage direction raster map can be used for r.distance or not? Do we achieve the same result?</div><div class="gmail_msg"><br class="gmail_msg"></div><div class="gmail_msg">Bundling the accumulation raster file massively increases the app setup file size whereas drainage direction only accounts 1/4th size of accumulation raster file. </div><div class="gmail_extra gmail_msg"><br clear="all" class="gmail_msg"><div class="gmail_msg"><div class="m_-5144060465956198424gmail_signature gmail_msg" data-smartmail="gmail_signature"><div dir="ltr" class="gmail_msg"><div style="font-size:12.8px" class="gmail_msg"><b class="gmail_msg">Best,</b></div><div style="font-size:12.8px" class="gmail_msg"><b class="gmail_msg">Ang</b></div></div></div></div></div></div><div dir="ltr" class="gmail_msg"><div class="gmail_extra gmail_msg">
<br class="gmail_msg"><div class="gmail_quote gmail_msg">On Wed, Mar 29, 2017 at 9:49 PM, Daniel Victoria <span dir="ltr" class="gmail_msg"><<a href="mailto:daniel.victoria@gmail.com" class="gmail_msg" target="_blank">daniel.victoria@gmail.com</a>></span> wrote:<br class="gmail_msg"><blockquote class="gmail_quote gmail_msg" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr" class="gmail_msg"><div class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg"><div class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg"><div class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg"><div class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg"><div class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg"><div class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg"><div class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg">Hi Ang,<br class="gmail_msg"><br class="gmail_msg"></div><div class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg">I had replied off list. I'm now replying to the list so other can comment<br class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg"></div><div class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg"><br class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg"></div>The idea is that to delineate watersheds, the outlet has to lie in a
place with high accumulation. So if you get your outlet points a bit
messed up, a way to force them to go to the right place is to use
r.distance.<br class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg"></div><br class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg"></div>I don't
have a specific code nor I recall the steps I've taken back in 2010, when I did this. But, looking at
the r.distance manual [1], this is what I'd try if I had to repeat the
process today:<br class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg"><br class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg"></div>1) Convert my outlet points to raster, each with a different category<br class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg"></div>2) Threshold your flow accumulation map in order to delineate the rivers (high flow accumulation)<br class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg">3)
Run r.distance to find the closest river line to each of your output
point. Check that you don't create any points to far away from the
original position.<br class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg"></div>4) Use the output of r.distance as the coordinates in r.water.outlet<br class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg"></div><div class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg"><div class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg"><div class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg"><div class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg"><br class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg"></div><div class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg">Cheers<br class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg"></div><div class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg">Daniel<br class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg"></div><div class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg"><br class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg">[1] - <a href="https://grass.osgeo.org/grass72/manuals/r.distance.html" class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg" target="_blank">https://grass.osgeo.org/grass72/manuals/r.distance.html</a></div></div></div></div>
</div><br class="gmail_msg"><div class="gmail_quote gmail_msg"><div class="gmail_msg"><div class="m_-5144060465956198424h5 gmail_msg"><div dir="ltr" class="gmail_msg">On Wed, Mar 29, 2017 at 12:55 PM Ang Sherpa <<a href="mailto:angsherpa232@gmail.com" class="gmail_msg" target="_blank">angsherpa232@gmail.com</a>> wrote:<br class="gmail_msg"></div></div></div><blockquote class="gmail_quote gmail_msg" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="gmail_msg"><div class="m_-5144060465956198424h5 gmail_msg"><div dir="ltr" class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg"><div class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg">Hi users,</div><div class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg"><br class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg"></div><div class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg">While using "r.water.outlet" to delineate watershed basin, although the coordinates of the stream was noted from google earth and fed into "r.water.outlet" module, it produces plain raster. </div><div class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg"><br class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg"></div><div class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg">Is there any solution to make sure that the coordinates of outlet point automatically snaps to the nearest line of stream in drainage direction map?</div><div class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg"><br class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg"></div><div class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg"><br class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg"></div><div class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg">Any words will be appreciated.</div><div class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg"><br class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg"></div><br clear="all" class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg"><div class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg"><div class="m_-5144060465956198424m_-8067708184178616528m_-4848570150643095785gmail_signature m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg" data-smartmail="gmail_signature"><div dir="ltr" class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg"><div style="font-size:12.8px" class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg"><b class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg">Best,</b></div><div style="font-size:12.8px" class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg"><b class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg">Ang</b></div></div></div></div>
</div></div></div>
_______________________________________________<br class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg">
grass-user mailing list<br class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg">
<a href="mailto:grass-user@lists.osgeo.org" class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg" target="_blank">grass-user@lists.osgeo.org</a><br class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg">
<a href="https://lists.osgeo.org/mailman/listinfo/grass-user" rel="noreferrer" class="m_-5144060465956198424m_-8067708184178616528gmail_msg gmail_msg" target="_blank">https://lists.osgeo.org/mailman/listinfo/grass-user</a></blockquote></div>
</blockquote></div><br class="gmail_msg"></div></div></blockquote></div>