[Talk-GB] Roundabout, ways and relationship policies

[Andy Allan]

On Wed, Jul 22, 2009 at 4:22 PM, Nicholas Barnes<nick at thebarnesfamily.eu> wrote:
> Shaun McDonald wrote:
>> I have seen many roundabouts split up so that the bridges can be added
>> properly, so started doing it myself some time ago.
>
> Which begs the question.... what is the point of tagging as way as a bridge?

Because the bridge exists, and we want to map it.

> Other than what the rendered map looks like (and I keep hearing that
> we're not meant to be tagging for the renderer)

You can tag anything you like so long as it's factually correct.

> I can't see the point
> of messing up

It's not messing it up, it's adding more factually correct information
which is widely accepted in OpenStreetMap as being useful.

> a perfectly formed roundabout with all parts set with the
> correct 'layer' tag when all you end up with is a roundabout which
> renders as badly as this one:
> http://www.openstreetmap.org/?lat=52.46457&lon=-1.70987&zoom=15&layers=0B00FFF

If you look at every other layer it renders fine, so it's hardly a
fundamental problem with the data.

> Surely it's perfectly obvious that if a road goes underneath another
> road, there must be a bridge involved.

It took me literally milliseconds to think of a case where that's not true.

> Sorry for the rant, but I've just fixed two roundabouts where the layers
> were all set incorrectly at about the time somebody added those bus routes.

Such are the joys of a wiki map.

Cheers,
Andy