<div dir="ltr"><div>The multiple water body situation arises frequently in my Alaska mapping. I have struggled over the years to tag them in such a manner that the names will render but without resorting to trickery to make that happen. A couple of years ago I happened on a group of three lakes, two of which contained islands and were already multipolygons created during an old import. The other was merely a small lake. The USGS Topo maps I use as my guide for naming things in these remote regions gave the name Three Lakes to the group. I created a multipolygon relation tagged with natural=water to contain them but for reasons I do not recall now, put the name Three Lakes on each of them. Perhaps I was struggling to get those names to display inside JOSM, or maybe it was just because I had so little experience with multipolygons of this type. Whatever. I made a note to myself to check after a time to see if Three Lakes was findable via a Nominatum search. I did that last week and found that they were not.</div><div><br></div><div>So I retagged them this time assigning the name "Three Lakes" to the relation containing the lakes and removing it from the individual lakes. I checked back again today, after a few days had elapsed, and was able to seach for and find Three Lakes. But also today, when I was checking the area in order to use it as an example for my reponse to this thread, I noticed that two of those lakes have individual names. I added the names but JOSM complained. Of course, it wanted something more than just a name. I added water=natural to each of those two lakes and was able to upload them successfully. So now my lakes are tagged with natural=water twice, once on each of their outer ways and once in the relation. If the natural=water tag is removed from the relation, the simple lake doesn't render as water. Where is the proper place for the natural=water tag?<br></div><div><br></div><div>I fool around with the tagging every time I create one of these monsters. Just last week I created another multipolygon relation to hold a pair of calderas named "Twin Calderas", one of which contains a lake. I searched for it today and found it but another mapper had edited it in order to "fix old style multipolygon". I asked him in a changeset comment what exactly he had done to fix it and he replied, "The old-style multipolygon (with only type=multipolygon tag) with the
two members on the left (one outer and one inner) was removed, the
correctly tagged multipolygon was updated to also include the inner from
the other multipolygon, because it also includes its outer." I'm reluctant to ask him to explain further because I'm clearly confused by his answer and indeed, by the entire concept.</div><div><br></div><div>I'll be following this thread closely to see if I can learn anything from it.</div><div><br></div><div>Dave</div><div><br></div><div>The Three Lakes relation is id:6,714,525</div><div>Twin Calderas relation is id:8,771,446<br>
</div></div><br><div class="gmail_quote"><div dir="ltr">On Mon, Oct 8, 2018 at 3:08 PM Martin Koppenhoefer <<a href="mailto:dieterdreist@gmail.com" target="_blank">dieterdreist@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><br>
<br>
sent from a phone<br>
<br>
> On 7. Oct 2018, at 21:46, marc marc <<a href="mailto:marc_marc_irc@hotmail.com" target="_blank">marc_marc_irc@hotmail.com</a>> wrote:<br>
> <br>
> I'm not sure it's necessary to create a value to repeat the type of <br>
> object already present in osm. otherwise it would require a value for <br>
> each type of object and a value for each type of possible combination <br>
> between theose types.<br>
<br>
<br>
what is “necessary” has to do with the use case someone has in mind, if you want to unambiguously map that there is a group of lakes with a common name for the group, it is indeed necessary to describe the thing with more tags than just a name.<br>
<br>
Cheers, Martin <br>
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</blockquote></div><br clear="all"><br>-- <br><div dir="ltr" class="m_-4261497262084392654gmail_signature" data-smartmail="gmail_signature"><div dir="ltr">Dave Swarthout<br>Homer, Alaska<br>Chiang Mai, Thailand<br>Travel Blog at <a href="http://dswarthout.blogspot.com" target="_blank">http://dswarthout.blogspot.com</a></div></div>