[OSM-talk] confused about roundabouts and ways

[Tom Chance]

Ahoy,

This is just how I am doing things, no guarantee that it's the Right Way (tm).

On Tue, 02 Jan 2007 18:10:02 +1100, Andrew Loughhead <andrew at incanberra.com.au> wrote:
> Is junction=roundabout applied to segments or a ways?

Ways, because segments may be phased out and aren't generally rendered (nor are their attributes).


> Lets say the roundabout is a junction of two different classes of road,
> highway=secondary and highway=unclassified, all four connecting roads
> are single carriageway, and all four connect to the roundabout with
> triangles.  The roundabout way would usually want to be
> highway=secondary. But if the roundabout way includes the triangles of
> the highway=unclassified road, then the triangles will render as
> highway=secondary, which will be ugly and misleading.

I would make the roundabout the same highway type as the 'highest' connecting road, so if it's a roundabout between a secondary road and some residential/unclassified roads, make the roundabout way secondary. If the connecting roads branch *significantly* then those triangles remain parts of those roads, not the roundabout, and use their tags, names and all. It would make sense for those triangles to have oneway=yes/true as well, just for navigation software.


> If a road has the same name each side of a roundabout, is each bit a
> separate way?  Or can they be disconnected parts of a single way?

I do two separate ways. In general roundabouts are good opportunities to break up long roads, though I can see that being really painful in towns like Milton Keynes!


> The editing guidelines say each direction of dual carriageway should be
> a separate way. If a road alternates between dual carriageway and single
> carriageway, is each part a separate way?  If so, does this apply to
> things like roundabout triangles, where the road is briefly dual
> carriageway?

Yes they should be separate ways. With the triangles I usually just extend one way all the way up to the triangle, then have two small oneway ways for the triangle part.


> Do roundabouts get a name attribute?

I'm not sure on this one, I think I do it a bit randomly. Always if they have a specific name, usually if there are houses on it, yes, and always with refs. I suppose the proper answer is "yes", unless roundabouts don't have a name and aren't officially named along with the road.

Regards,
Tom