[Talk-us] Complex intersection mapping

Tod Fitch tod at fitchdesign.com
Mon Oct 14 23:30:39 UTC 2013

The latter (after) version matches the traffic signal wiki http://wiki.openstreetmaps.org/wiki/Tag:highway%3Dtraffic_signals#Tag_all_incoming_ways

It makes sense to me and is the way I prefer.


Sent from my mobile device. Please excuse my brevity.

Martijn van Exel <martijnv at telenav.com> wrote:
>Hi all,
>Here at Telenav we have been looking at complex intersections and we
>have set about editing some of these intersections in a way we feel
>represents the situation on the ground better than their original
>state, and because of that, works better for us. We have received some
>feedback on our edits so we wanted to take a step back and see what we
>(as the OSM community) think is the preferred way to map these
>So what are we talking about? Intersections like this one, where one
>or more dual carriageways come together at an at-grade intersection:
>One of my colleagues at Telenav has remapped this intersection as
>The main difference, and the source of some feedback we have received
>over the past few days, is that the dual carriageway roads are
>straightened out, creating multiple intersection nodes (4 in this
>case) instead of the original single intersection node that connects
>all the incoming and outgoing ways. That technique turns out to yield
>more reliable and correct routing and guidance ('keep left, turn
>right') through these intersections in our testing. But of course,
>that cannot dictate how we map as a community, so let's discuss.
>Some of the feedback we have received about these edits points to a
>statement on this wiki page:
>https://wiki.openstreetmap.org/wiki/TIGER_fixup#Braided_streets: 'It
>is a reasonable and well-used technique to bring the ways of dual
>carriageways back to a single point at intersections to facilitate and
>simplify the mapping of control devices and turn restrictions.' In my
>mapping across the US, my personal experience has been that this
>technique is in fact used, but the 'after' technique with straightened
>out ways is actually much more common. I personally prefer that
>technique as well - I think it is more pleasing to the eye, represents
>what is on the ground better, and is and easier to read. So my feeling
>was that this mapping practice would not be disputed. It turns out I
>was wrong, so I want to see what the consensus is on mapping
>intersections of this type - or perhaps there is none and we can work
>together to get there?
>Martijn van Exel
>OSM data specialist
>Talk-us mailing list
>Talk-us at openstreetmap.org
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