[Tagging] area=yes on polygones (was Block names)

Tobias Knerr osm at tobias-knerr.de
Sat Apr 28 11:04:59 BST 2012

28.04.2012 11:34, Peter Wendorff wrote:
> Let's consider two well known examples:
> building=* => usually by default area=yes, a non-closed way may be
> considered as invalid(?)

Yes, it would be invalid. As documented in the wiki, the building key
(ignoring building=entrance and the like) is for areas only. And this
means that it isn't really a relevant example here.

> A common default value would lead to either
> ~56M area=yes on buildings
> or
> ~52M area=no on highways

I assume that this is a misunderstanding, because I don't think anybody
was suggesting that area=yes should be used together with tags that are
unambiguous anyway. My suggestion, and current practice as far as I can
tell, is:

* If a tag can only be used on areas, or only on ways, you don't need an
area tag.
* If a tag can be used on both areas and ways, the default
interpretation is that it is a way, and area=yes is required to make it
an area.

> On the other hand, a fenced field is landuse=* (and in this respect
> implicitly area=yes) and barrier=fence (and here implicitly area=no),
> and that's fine.

Actually, that particular style of using barrier=fence has always been a
bit of a hack and it's probably not the best example of clean tagging.

But since landuse cannot be used on ways, and barrier=fence cannot be
used on areas (well, it can, but then it is treated as a "this area is
fenced" attribute and not as a very wide fence), this is again not an
example where area=yes or area=no is required at all.


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