[OSM-newbies] Validation Error
richard at weait.com
Mon Feb 1 00:03:34 GMT 2010
On Sat, Jan 30, 2010 at 1:36 PM, Mike N. <niceman at att.net> wrote:
> For no-turn intersections in terms of the map data, it is correct to just
> ignore the error since routing will be correct. The only reason to put in
> intersection nodes plus turn restrictions would be so that following mappers
> don't blindly fixup validator errors by just joining the 2 ways.
> A NOTE tag to other mappers placed on the ways might be a better solution.
> I find turn_restriction relations to be extremely complicated (perhaps
> overly complicated, but I don't have a simpler way offhand). A simple "no
> left turn allowed" T intersection tuned into an extra split for the way at
> the T, followed by 2 turn_restriction relations to cover the simple case.
> I'd hate to model this for a more complex intersection.
I recommend placing a node at road junctions that are a level crossing
even if turns are prohibited. While it may be simpler to omit the
junction where turns are prohibited for motor vehicles, this ignores
pedestrians and bicycles (depending on local law).
If the roads are physically connected, we should connect them with a
node. To do otherwise is to break the topology. If you aren't
comfortable with building the turn restrictions, consider adding a
note to future mappers, or on openstreetbugs so somebody else can
Junctions get a node. Bridges do not.
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