[OSM-talk] route=road - What's that all about then?

[Andy Street]

On Thu, 21 Aug 2014 19:20:06 +0100
"Dave F." <davefox at madasafish.com> wrote:
> http://ra.osmsurround.org/analyzeRelation?relationId=18159&_noCache=on
> 
> This route relation appears to be just for the B3070. Isn't that a
> waste of time as it's covered by the ref tags on the ways?
> 
> I thought route relations were a way to allow tagging of journeys
> taken over numerous types of ways. Any reason why I shouldn't delete
> it?

IIRC route=road relations were suggested to fix the problem of
multiplexing (two or more numbered routes sharing the same
physical road). In this instance the B3070 appears to be a route
between Wareham and Lulworth Cove which multiplexes with the A352 at
Worgret Hill. Simply doing an Overpass query for ref=B3070 would be
insufficient to return all of the ways required to traverse the route
from start to finish, hence the need for a relation.

Ironically the the only section currently missing from the relation
(the A352) is the bit that makes the relation necessary!

-- 
Regards,

Andy Street