[Talk-us] State Route relations (was: Highway TaggingConsensustoImprove OSM (and address some of 41 latitude's concerns))

Mike N. niceman at att.net
Sat Oct 16 16:59:19 BST 2010

> The potential problem I see is when you have a road that alternates
> frequently between single- and dual-carriageways (which many state
> routes do, and even a lot of US highways).  How do you represent this in
> a single relation?
> 1) Put single-carriageways in once, with no role.  Or, with
> "role=north/south".  Either way, this is difficult to recognize and
> parse automatically.  And aren't members of a relation ordered inside
> the relation?  (I know JOSM shows icons for whether a way is connected
> to the ways before and after it in a relation.)  The ordering loses any
> meaning under this method.

  The way I've done this, and seen it done, is to put single carriageways in 
once with no role.     I'm not sure I understand the difficulty of parsing 
it automatically - please elaborate.

  Ordering has no meaning in road route relations.   JOSM can sort them as a 
debugging tool.   Ordering is too easily lost, as seen in the constant loss 
of bicycle route relations sort order in Europe.

> In my view, having separate relations for each direction, and a
> super-relation to hold them solves this problem.  But maybe there's some
> argument against them that I've missed.

   It certainly will work also - my only complaint is juggling the 3 
relations in the editor.   Perhaps this won't be a problem after the road 
network is comprehensively tagged.


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