[OSM-talk] wiki tag page template: ways vs areas vs relations

[Martin Koppenhoefer]

2014-10-07 11:05 GMT+02:00 moltonel 3x Combo <moltonel at gmail.com>:

> Hi List,
>
> all tag pages on the wiki have a sidebar[1] that tells which element
> (node, way, area, relation) the tag applies to. Since an "area" is
> either a closed way or a multipolygon relation, my understanding has
> always been that if a tag is only meant for an area (for example most
> landuse tags), it shouldn't be documented as usable on "ways" and
> "relations" in general. In other words, for that template's usecase,
> ways/area/relations are separate sets, despite sharing primitives.
>
> Is that everyone else's understanding too ? In that case, I'll mention
> that fact in the template's documentation, and keep an eye out for
> misdocumented tags.
>
> [1]:http://wiki.openstreetmap.org/wiki/Template:ValueDescription
>


+1
Besides this, in the past I have so often encountered wrong/incomplete
settings (compared to what is actually done, and to what should / can be
done according to my own understanding) that I generally ignore these
icons. Do we really need them? Is there any benefit e.g. for data
consumers, compared to looking at actual usage numbers and cases?

E.g. the area key: http://wiki.openstreetmap.org/wiki/Key:area
the setting is currently "not on ways", but that's nonesense because you
need this key on some ways (e.g. linear closed barriers) with area=no to
avoid confusion.

Or the key for a phone booth:
http://wiki.openstreetmap.org/wiki/Tag:amenity%3Dtelephone . According to
the wiki it should be mapped only on nodes (and I agree that this is
preferable for the current state of mapping), still some people have used
this on ways and I don't think it is "wrong" (actually an area is better
for everything that is not a true point or a very tiny area in reality,
e.g. a peak).

Or the key "bench" http://wiki.openstreetmap.org/wiki/Tag:amenity%3Dbench
Currently defined for nodes and ways, but areas would make sense in some
cases (when you'd want to express a particular shape for instance).

Often the relation setting is set to no, but how can this be? Aren't
mappers encouraged to invent new relation types just as they can invent new
tags? Can't any object be part of a site relation for instance? Will we
check for every new relation type that gets proposed and/or introduced (by
the way, what does this mean in OSM, "introduced"?) all objects in the wiki
if their "applicable to" section complies with the new relation type? Which
relation types are actually meant with the "relation" setting in this
template?

cheers,
Martin
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