[OSM-talk] Roundabouts and routing

[Lester Caine]

Jonathan Waller wrote:
> With regards to solution 1) I have never noticed a sliproad onto a roundabout
> tagged as junction=roundabout (UK East Midlands).  Where is this common
> practice?  If this is not too widely used then it might be worth retagging, but
> I don't know how easy it would be to automatically detect these.

Certainly the roundabouts near here all have islands in the middle of the 
approach, so these need to be mapped, if only for the pedestrian route around 
them. They are all tagged as part of the approach road, but obviously have the 
correct direction arrows ... which they need!

I think the main problem here is not so much anything to do with OSM, but how 
the portable devices work. TomTom has this very annoying habit of announcing 
some silly side road or even layby as a junction then totally ignoring the 
merges with a motorway a mile or so later. It is the interpretation of the data 
that is the problem, not the data itself, and if anything that needs to be 
handled in the conversion process to the device not on the raw map? Bodging the 
data so that the device does what you want ;)

-- 
Lester Caine - G8HFL
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