[Tagging] How to tag named group of named water areas?

Dave Swarthout daveswarthout at gmail.com
Fri Nov 2 23:00:06 UTC 2018

Of course. The Trans Alaska Pipeline is as good an example as any. It is a
man_made oil pipeline that stretches 1300 km across the entire state of
Alaska. The relation contains 280 members. The reason there are so many
members is because the pipeline way has been split into many individual
pieces, separate ways, that have certain differing characteristics, e.g.
where it runs underground or crosses a river on a bridge. The tagging for
any specific way deals with those differing characteristics. A section
might run for several miles underground and then emerge. At that point the
pipeline way must be split into a section with location=underground and the
emergent section with location=overground. Now it comes to a river that it
crosses on a bridge. The pipeline way is split again into a section that
has the tags bridge=yes and layer=1. You do the same thing to a highway
where the number of lanes changes, or maxspeed. Each change requires you to
split the way.

Now say you've been tagging each piece with all the tags required rather
than the relation. You decide to add a Wikipedia tag to the pipeline. Using
your method, you must edit every piece of the pipeline, all 280 sections of
it, and add the Wikipedia tag. Tagging the relation with the Wikipedia
entry, however, requires only one edit. To make matters worse, let's just
say you misspelled the Wikipedia tag value. You meant to write
"wikipedia=en:Trans-Alaska Pipeline System" but forgot to include the "en:"
prefix. Back you go to your editor, editing all 280 pieces again. That's
why I say tagging it this way is a maintenance nightmare.

I would only use tags on a particular way when its characteristics demand
it. Tags that apply to the entire pipeline belong in the relation. Tags
like the Wikipedia tag, substance=oil, man_made=pipeline, operator,
alt_name, etc., belong on the relation. However, tags like bridge and
location, tags that apply to individual sections or ways, get applied to
the ways and not the relation because they don't apply to the entire

On Sat, Nov 3, 2018 at 4:25 AM Mateusz Konieczny <matkoniecz at tutanota.com>

> 2. Nov 2018 01:04 by daveswarthout at gmail.com:
>  The only tags that should appear on the ways themselves are attributes of
> those ways, for example, location=overground or location=underground, and
> tags for bridge and layer. Everything else, Wikidata, substance=oil,
> man_made=pipeline, etc, should appear only on the relation.
> I am not convinced that it is a good idea.
> If those tags appear on each way in addition to the relation, maintaining
> any consistency in the tagging on this beast would be almost impossible.
> Can you give examples of task that you claim to be almost impossible?
> _______________________________________________
> Tagging mailing list
> Tagging at openstreetmap.org
> https://lists.openstreetmap.org/listinfo/tagging

Dave Swarthout
Homer, Alaska
Chiang Mai, Thailand
Travel Blog at http://dswarthout.blogspot.com
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstreetmap.org/pipermail/tagging/attachments/20181103/61ca3dcf/attachment.html>

More information about the Tagging mailing list