[talk-au] Lanes [Was] Roundabouts and routing

[Ross Scanlon]

> My advocacy is to treat ways like relations, you group the lanes into
> a way and the tags from the way cascade to the lanes or can be
> overriden, however for small screens you only use ways and ignore
> lanes, although the lanes could be used for routing/turning even if
> not displayed.

This is similar to the lane_group relation proposal but it gives backward compatibility.

ie Use a way to describe the topological position and then use a lane_group relation to describe all the lanes associated with it.

The advantage of this is that if you don't want the lane information you can just process the ways and ignore the relation totally.

 
> > They look like they will cover what we have been discussing.  We may need to get one of these pushed along, or offer assistance to do so.
> 
> No one in a position to do something about this seems to care, so it's
> unlikely which is why people are using ways to represent lanes.

As per usual.  Isn't it a case of tag as appropriate then, osm lets us tag as required so how about we (Australian osm users/mappers) make a decission as to what we are going to tag and do it consistently.  Then put it on the Aust Tagging page so everyone uses it.
 
> > 1. not mapping lanes as individual ways, as it will mean lots of work to modify them later on.
> 
> And because it's the wrong thing to do imho, since a way is a physical
> thing, lanes aren't usually physically seperated from each other.

Agree totally.
 
> > 2. Tag sections of ways with lanes=* where there are junctions like this.  Other areas as you see fit.
> 
> Most ways can be assumed to be 2 lanes, so this is only needed if
> there is more or less than 2 lanes, although tagging 2 lanes would at
> least show it has been surveyed/mapped properly rather than not
> knowing if the information is missing.

So best to tag all where these intersections occur.
 
> > 3. Make a decission on which of the above proposals for lanes we want to support and advocate it.
> 
> I'm not sure if either are the best way to do it, I'd love for proper
> cascading of tags etc from ways -> lanes, and so on, but those
> proposals suggest some weird tagging scheme (1) or using relations (2)
> where I feel the way should be done is to assume a way is like a
> relation that groups lanes together.

Which is what the lanes_group relation would do as the relation is attached to the way.


-- 
Cheers
Ross