Stephan's reference to Wikipedia helps to properly define source in this context :
Wikipedia: confluence: In geography, a confluence is the meeting of two or more bodies of water. Also known as a conflux, it refers either to the point where a tributary joins a larger river, (main stem), or *where two streams meet to become the source of a river of a new name*, such as the confluence of the Monongahela and Allegheny rivers in Pittsburgh, Pennsylvania creating the Ohio River. The point of confluence isn't a "source" in the normal sense (that is usually a spring, glacier or pond) but it does indicate the beginning of a new named river and as such, justifies special treatment IMO. In the situation where that beginning point is a spring the two tags one might use, waterway=source and natural=spring, do not interfere with one another. The other Wikipedia article about River_source favors using the source of the named river's longest tributary as its source, so it disagrees with the first article. In practice, an ordinary OSM user probably will not usually be able to determine such a source point unless he or she happens to be in the field with map and measuring tape. I think waterway=source is a good candidate for inclusion in the OSM Wiki but I'm not anxious to add it. Editing that blasted Wiki is so difficult I usually avoid it at all costs. The waterway page looks easily editable so perhaps I'll give it a try if we are all in agreement that such an addition makes sense. The Relation:waterway page uses a table. No way I'm going near that page LOL I know it's difficult to find consensus on this list, or anywhere for that matter, so I'll wait until all the comments are in before going ahead with any change to the Wiki. Thanks, Dave On Sun, Feb 26, 2017 at 11:04 PM, Stephan Knauss <o...@stephans-server.de> wrote: > > how about extending the waterway relation with a member role which can > indicate either the "spring" or the "source" in case of a "creation" of a > river by multiple tributary rivers? > > Not sure how it would best be called. Source? Origin? Confluence? Is there > a specific hdyrology term for this? > > Wikipedia might indicate that "source" is the right word to use. > > https://en.wikipedia.org/wiki/Confluence > > https://en.wikipedia.org/wiki/River_source > > If this is also suitable for a spring, then changing the role spring to > source would do the trick. > > https://wiki.openstreetmap.org/wiki/Relation:waterway > > While you update the wiki: I feel the "tributary" role also deserves to be > documented in the wiki page. It is used nearly 7.000 times. > > Stephan > > > On 26.02.2017 09:41, Dave Swarthout wrote: > >> That's interesting. I wonder if the tagging of tourism=attraction is >> totally appropriate but surely a waterway=source tag is. Presumably the >> mapper was trying to indicate that the source of that stream is where >> that node is. >> >> I'm going to start using the tag myself and let data consumers figure it >> out if they wish. After a while I'll consider adding it to the Wiki. >> There are a few instances of the tag in use already. >> >> On Feb 26, 2017 2:23 PM, "Martin Koppenhoefer" <dieterdre...@gmail.com >> <mailto:dieterdre...@gmail.com>> wrote: >> The point where it starts doesn't (yet) have any meaningful tags, >> just a property disguised as a >> feature: http://www.openstreetmap.org/node/135500355 >> > > > _______________________________________________ > Tagging mailing list > Tagging@openstreetmap.org > https://lists.openstreetmap.org/listinfo/tagging > -- Dave Swarthout Homer, Alaska Chiang Mai, Thailand Travel Blog at http://dswarthout.blogspot.com
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