<html><head></head><body>You seem to be describing a watershed, which was recently discussed.<br><br><a href="https://lists.openstreetmap.org/pipermail/tagging/2018-September/039026.html">https://lists.openstreetmap.org/pipermail/tagging/2018-September/039026.html</a><br><br>Phil (trigpoint) <br><br><div class="gmail_quote">On 4 October 2018 15:46:19 BST, Kevin Kenny <kevin.b.kenny@gmail.com> wrote:<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
<pre class="k9mail">In some maps that I render, I want to show the divide between a couple<br>of major river basins. (I have a good DEM for the area in question and<br>can derive the line readily.)<br><br>In light of the recent thread on topographic prominence, I wonder if<br>this is sufficiently interesting information at least to push it to<br>OSM. (If not, that's fine, I have a PostGIS database and a bucket of<br>shapefiles and know what to do.)<br><br>If it is sufficiently interesting, the question then arises: how to map/tag it?<br><br>'natural=ridge' comes to mind, and the divide in question has a local<br>name. (The 'Catskill Divide' separates the basins of the Hudson and<br>Delaware Rivers.) This approach appears to run into problems, as I<br>read the Wiki. I see:<br><br><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #729fcf; padding-left: 1ex;">The way should connect saddle points and peaks, and the arrows should point upwards.<br></blockquote><br>That may be all right for a ridge ascending the flank of a single<br>mountain, but what I'm talking about is the spine of a range, with the<br>ridge traversing dozens of named peaks. Even with a single mountain,<br>if there are false summits, the arrows on a single way cannot point<br>upward all the time! (And the wiki is clear that the<br><br>Do I misread, and should the reading instead simply be that the<br>arrowhead should be higher than the arrow tail? In that case, I could<br>break the divide into two ways, with a common endpoint at the highest<br>summit in the range.<br><br>Consider this a low-priority item. I have (or will have - there is a<br>bit of debugging yet) the data. I know how to render them. I'm happy<br>enough with a shapefile or a private PostGIS table if others aren't<br>interested.<hr>Tagging mailing list<br>Tagging@openstreetmap.org<br><a href="https://lists.openstreetmap.org/listinfo/tagging">https://lists.openstreetmap.org/listinfo/tagging</a><br></pre></blockquote></div><br>-- <br>Sent from my Android device with K-9 Mail. Please excuse my brevity.</body></html>