[Tilesathome] Proposal temporay tags -- the solution?

[Marc Schütz]

> Why is nesting such a bad thing?
>

I think nesting is only the sympton. The problem is that bridge/tunnel/etc. 
should be treatible as independent of all the other tags a particular object 
might have, because all bridges should basically look the same. The only thing 
where they differ is the width of the object. But there is no way for a rule to 
know which width it has, without looking at the highway, railway, or whatever 
other tags that might be relevant.

So there are tons of CSS styles, each of which repeats the width information 
(railway-rail-bridge-casing, railway-light-rail-bridge-casing, ...) whereas in 
fact just one declaration should suffice, if it could somehow reference the 
width of the underlying object. At the same time, it would make a lot of 
nesting unnecessary.

And width is only the most prominent example; there are others too. For 
example, there's a problem when an object has a text label, a house number, and 
a symbol. Different offsets have to be applied depending on which combination 
of these is present.

Regards, Marc

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 197 bytes
Desc: This is a digitally signed message part.
URL: <http://lists.openstreetmap.org/pipermail/tilesathome/attachments/20090131/06e159f7/attachment.pgp>