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

[Jochen Topf]

On Di, Okt 07, 2014 at 01:20:14 +0200, Martin Koppenhoefer wrote:
> 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?

I think they are better than nothing. Your arguments work for about everything
in OSM. Because we have so much freedom in OSM we can always throw our hands in
the air and say: This is all so complex and there is no way I can ever describe
the complexity so lets give up. And only because in theory we can invent new
relation types all the time, in practice there is often no software that uses
them, so telling the user that they can do everything they want just doesn't
make any sense. For phone booths, everybody uses nodes, everybody understands
that, the software understands that. For practical purposes this is what we
do and what we document. Of course all these things change over time and maybe
somebody it will be common place to do it differently, but thats what we have
now and what we should document.

Maybe we should have a tool that compares object counts for the different types
from taginfo with the wiki documentation and complain if they seem to be out
of whack? Main problem there is that taginfo doesn't know about "areas", but
only about ways and relations.

Jochen
-- 
Jochen Topf  jochen at remote.org  http://www.jochentopf.com/  +49-721-388298