<div dir="ltr">Great job.<div><br></div><div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, May 5, 2020 at 11:56 AM Giuseppe Amatulli <<a href="mailto:giuseppe.amatulli@gmail.com">giuseppe.amatulli@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div class="gmail_quote"><p>Dear GRASS Team<br></p>
<p>I am running a global analysis where I need to use "tiles" as
computational units in which I use the following three commands:</p>r.watershed -b elevation=elv depression=dep accumulation=flow drainage=dir_rw flow=pixel_area memory=100000 --o --verbose <br>r.stream.extract elevation=elv accumulation=flow depression=dep threshold=0.05 direction=dir_rs stream_raster=stream memory=100000 --o --verbose <br>r.stream.basins -l stream_rast=stream direction=dir_rs basins=lbasin memory=100000 --o --verbose
<div><br></div><div>The basins that were not completely within a tile (resulting in
broken-basins) have been removed (see below the three tiles in
Figs. 1,2,3 including only entire basins), </div>
<div>and now I'm in the phase of merging all the tiles having only
complete basins.<br>
</div>
<div><br>
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<div>When I merge the tiles (Fig 4), some basin borders do not match
perfectly, and some areas have NoData (see Fig 5,6) or have the
Basin ID of the below basin (Fig 7). </div>
<div>I noticed that these phenomena appear only when I merge tiles
that have very large broken-basins that can not be included in the
tile due to RAM limitations.</div>
<div><br>
</div>
<div>My thought is that r.stream.basins needs the entire dimension
of two adjacent basins to be able to detect the border without gap
and without a potential random selection. </div>
<div>Is there any part of the r.stream.basins code that I can potentially check and eventually hack to avoid this problem? </div>
<div><br>
</div>
<div>For the rest, all the RAM limitation and other problem have been
solved soon we will have a global stream network and basin
delineation performed 100% in GRASS!!! </div><div><br></div>
<div>Thank you </div>
<div>Best Regards </div>
<div>Giuseppe <br>
</div>
<p><br></p>
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<div>Fig 1. Left Tile</div>
<div><img src="cid:171e628adb9cb971f161" alt="image.png" width="542" height="343"><br>
</div>
</div>
<div><br>
</div>
<div><br>
</div>
<div>Fig 2. Center tile </div>
<div><img src="cid:171e628adb9cb971f162" alt="image.png" width="312" height="524"><br>
</div>
<div><br>
</div>
<div><br>
</div>
<div>Fig 3. Right Tile </div>
<div><img src="cid:171e628adb9cb971f163" alt="image.png" width="542" height="247"><br>
</div>
<div><br>
</div>
<div><br>
</div>
<div>Fig 4. Merge all the tiles </div>
<div><img src="cid:171e628adb9cb971f164" alt="image.png" width="542" height="286"><br>
</div>
<div><br>
</div>
<div><br>
</div>
<div>Fig 5. Gap -> small white area </div>
<div>
<div><img src="cid:171e628adbacb971f165" alt="image.png" width="542" height="366"><br>
</div>
</div>
<div><br>
</div>
<div><br>
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<div>Fig 6. Gap -> small white area <br>
</div>
<div><img src="cid:171e628adbacb971f166" alt="image.png" width="518" height="542"><br>
</div>
<div><br>
</div>
<div>Fig 7. boarder Basins inconsistency among tiles <br>
</div>
<div><br>
</div>
<div>
<div><img src="cid:171e628adbacb971f167" alt="image.png" width="563" height="177"><br>
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<div>Giuseppe
Amatulli,
Ph.D.<br>
<br>
Research
scientist at<br>
<span>School
of Forestry
&
Environmental
Studies<br>
</span><span>Center
for Research
Computing</span><br>
Yale
University</div>
<div>New Haven,
CT, USA</div>
<div>06511<br>
<div>
Teaching: <a href="http://spatial-ecology.net" target="_blank">http://spatial-ecology.net</a></div>
Work: <a href="https://environment.yale.edu/profile/giuseppe-amatulli/" target="_blank">https://environment.yale.edu/profile/giuseppe-amatulli/</a>
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