[Tagging] Relation for saying "x is attached to y"?

[M∡rtin Koppenhoefer]

2010/8/29 Pieren <pieren3 at gmail.com>:
> On Sun, Aug 29, 2010 at 11:37 AM, Nathan Edgars II <neroute2 at gmail.com>
> wrote:
>>
>> Perhaps a site relation? I'm not sure it's necessary; any application
>> that needs that information can calculate whether the polygons
>> overlap.
>>
>
> Yes, the topology shows what is "inside" or "outside" the polygon. And you
> can use the tag "layer" to say what is on the top of what.


+1, but site-relations might still be useful in the context of power
generators. There are situations where the single objects do not
overlap but are side a side, for example you might have 3 generators
with 3 chimneys and want to model which chimney is connected to which
generator.

cheers,
Martin