[OSM-talk] Zonal restrictions.

[Ben Laenen]

On Wednesday 13 May 2009, Dave Stubbs wrote:
> Where "zone" is a known geographic area?
> A bounding way with tags like:
>  zone = restriction
>  maxspeed = 20kph
>  parking = no
>
> seems like the best way to do it to me if you don't want to just
> replicate the tags on everything (and I can understand why you
> wouldn't want to do that).

Except it's not a geographic area, but rather a set of streets with that 
restriction. If a bridge or tunnel without the restriction goes 
over/under a street with the restriction you'll have a problem.

> I really wouldn't recommend relations for specifying what things are
> inside an area. It's a waste of two entire dimensions our dataset
> happens to have.

So while it may work for many zonal restrictions to use an area 
(although even then there are still issues) you need another way as 
well due to the bridge/tunnel issue, and that other mehod can only be 
relations.

Ben