[OSM-talk] Pedestrian crossings and barriers

Peter Miller peter.miller at itoworld.com
Sun Jul 29 21:53:23 BST 2007

Sure. I think the only thing we need to do at this point is clarify that
traffic_signal is to be used at the junction node or alternatively at a node
on the approach. A new feature traffic_signalhead is to be used for the
column itself; this would then allow some random signal modelling software
to be linked in at a later point.

Personally I will be ignoring signal heads in Ipswich at this stage, but
will be adding traffic_signals.


> -----Original Message-----
> From: David Earl [mailto:david at frankieandshadow.com]
> Sent: 29 July 2007 20:55
> To: Peter Miller
> Cc: 'Andy Allan'; 'Tom Chance'; talk at openstreetmap.org
> Subject: Re: [OSM-talk] Pedestrian crossings and barriers
> On 29/07/2007 20:07, Peter Miller wrote:
> > This seems to be one of those threads connected to a can of worms, and
> ok we
> > also can't upload anything today so we have got time to talk.
> >
> > Would it not be reasonable to mark the central node of a simple junction
> > with 'highway=traffic_signal'. The simulator, router and renderer will
> all
> > assume that there is a column and a stop line on each approach and will
> > assume that pedestrians will be able to cross at certain times of the
> cycle.
> >
> > For more complex junctions should we not put a node in the highway at
> the
> > stop line on each approach? A rendered might show an actual signal
> column
> > offset a little to the side of the road and appropriate road markings; a
> > vehicle routing program will add in a delay, and pedestrian routing
> engine
> > will assume someone can cross.
>  > ...
> Well, I haven't modelled any junction in Cambridge as more than one node
> other than roundabouts and links across dual carriageways which are
> usually two, so the point is moot from my pov.
> But if you want junction modelling I think there is _much_ more to it
> than just the signals on the approaches. If you look at what Simon
> Nuttall has done (via Google maps) on the Cambridge Cycling Campaign
> route planner, you'll see he has junctions to the level of every
> approach lane (some of which have advance stop lines on them and some
> don't), the multiple ways a cycle gets across a junction and so on.
> I think the way to handle this is to have a separate junction modelling
> structure which the simple node refers to, so you can get a complex
> junction model if you want it.
> But I also think it would be better use of our time at the moment to be
> broadening the mapped area than to concentrate on this level of detail.
> Later perhaps.
> But if you do want each signal head etc, how about using a separate tag
> for that, so we can just plop a simple icon on the junction in response
> to one tag, but model the junction in more detail via others. Let's make
> it easy on the renderers while still allowing for richness of data.
> David

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