<html><body><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:16px"><div dir="ltr" id="yui_3_16_0_1_1423859737696_4223"><span id="yui_3_16_0_1_1423859737696_4397">I don't know if you have tried this yet, but you may also want to look at r.terraflow. It does both D8 (single flow direction) and multiple flow direction (flow is partitioned, according to the steepness of slope, to all directions that are lower than the central cell). Supposedly you can also switch from MFD to SFD once flow exceeds a threshold, but I have not been successful at doing this. It would be a simple simulation of channelization though. <br></span></div><div id="yui_3_16_0_1_1423859737696_4529" dir="ltr"><span id="yui_3_16_0_1_1423859737696_4397"><br></span></div><div id="yui_3_16_0_1_1423859737696_4530" dir="ltr"><span id="yui_3_16_0_1_1423859737696_4397">Just set the D8 flag in the options tab, otherwise it will give you MFD by default. <br></span></div><div id="yui_3_16_0_1_1423859737696_4414" dir="ltr"><br><span id="yui_3_16_0_1_1423859737696_4397"></span></div><div id="yui_3_16_0_1_1423859737696_4398" dir="ltr"><span id="yui_3_16_0_1_1423859737696_4397">-Thayer</span></div><div id="yui_3_16_0_1_1423859737696_4546" dir="ltr"><span id="yui_3_16_0_1_1423859737696_4397"><br></span></div><div id="yui_3_16_0_1_1423859737696_4432" dir="ltr"><span id="yui_3_16_0_1_1423859737696_4397"></span></div><br> <div id="yui_3_16_0_1_1423859737696_4226" style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"> <div id="yui_3_16_0_1_1423859737696_4225" style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"> <div id="yui_3_16_0_1_1423859737696_4227" class="y_msg_container"> <hr size="1"><font size="2" face="Arial"><b><span style="font-weight:bold;"></span></b></font>Date: Fri, 13 Feb 2015 11:12:30 -0700<br>From: Thomas Adams <<a id="yui_3_16_0_1_1423859737696_4230" ymailto="mailto:tea3rd@gmail.com" href="mailto:tea3rd@gmail.com">tea3rd@gmail.com</a>><br>To: "<a id="yui_3_16_0_1_1423859737696_4264" ymailto="mailto:grass-user@lists.osgeo.org" href="mailto:grass-user@lists.osgeo.org">grass-user@lists.osgeo.org</a>" <<a id="yui_3_16_0_1_1423859737696_4229" ymailto="mailto:grass-user@lists.osgeo.org" href="mailto:grass-user@lists.osgeo.org">grass-user@lists.osgeo.org</a>><br>Subject: [GRASS-user] Question about r.watershed and flow accumulation<br> grid<br>Message-ID:<br> <<a id="yui_3_16_0_1_1423859737696_4228" ymailto="mailto:CAGxgkWgefeTtcjZWKi3JP8wj79Eb0j3fZsf6hGzT8m9-dgce6w@mail.gmail.com" href="mailto:CAGxgkWgefeTtcjZWKi3JP8wj79Eb0j3fZsf6hGzT8m9-dgce6w@mail.gmail.com">CAGxgkWgefeTtcjZWKi3JP8wj79Eb0j3fZsf6hGzT8m9-dgce6w@mail.gmail.com</a>><br>Content-Type: text/plain; charset="utf-8"<br><br>Hello all!<br><br>I'm making use of the flow accumulation grid in GRASS 6.4.5 generated from<br>r.watershed using the SFD (D8) flow algorithm. The DEM has a 250m spatial<br>resolution. What I'm getting is a break in the flow accumulation in a few<br>locations which is causing me serious problems with subsequent processing<br>(with help from some here, I have put together some scripting to generate a<br>pixel connectivity file for a distributed hydrologic model).<br><br>Besides going to a higher resolution DEM, are there any thoughts as to how<br>I can eliminate these flow accumulation breaks?<br><br>Thank you,<br>Tom<br><br>--<br>-------------- next part --------------<br>An HTML attachment was scrubbed...<br>URL: <<a id="yui_3_16_0_1_1423859737696_4354" href="http://lists.osgeo.org/pipermail/grass-user/attachments/20150213/9306343f/attachment-0001.html" target="_blank">http://lists.osgeo.org/pipermail/grass-user/attachments/20150213/9306343f/attachment-0001.html</a>><br><br></div> </div> </div> </div></body></html>