> Date: Tue, 27 Aug 2013 23:35:45 +0200 > From: [email protected] > To: [email protected] > Subject: Re: [Tagging] Micro mapping traffic signals > > On Tue, Aug 27, 2013 at 11:22 PM, Vincent de Château-Thierry > <[email protected]> wrote: > > > This only deals with single traffic light mapping and will not solve the low > > scale rendering issues (how to put a single icon for multiple traffic > > lights) and the routing through multiple synchronised traffic lights. > > > It's not similar to the turn restriction relation. We don't need roles > like "from", "to", "via". We just have to represent the controlled > intersection and its traffic lights. The intersection (one or x nodes > of the highways junctions) is a member of the relation with a role > e,g, "intersection" or "junction". The traffic lights individual nodes > are also member of the relation with a role like "traffic_light". > A router is only interested to know if the intersection is controlled > or not; it does not care if it's by one or three traffic lights, or if > it is by two consecutive synchronized traffic lights. For the > renderer, if the relation contains only one member with role > "junction", it can put the icon on this node. If we have more than one > member with this role, it can calculate a centroid of all the > junctions nodes. > > Pieren >
Not completely true. There are some places that would need the "from", "to", & "via" tags for a traffic light relation. I know of two such places here in Pittsburgh, PA, USA on an undivided road within .5 miles of each other. Both of them are on the Liberty Bridge where one direction has traffic lights to control ramp traffic + the outbound lanes, while the inbound lanes have no traffic lights at all. Here are the nodes where I've already tagged them as "normal" traffic lights, but added a "note" tag for now to mention which direction the traffic lights effect ( [1] & [2] ). And here's a quick StreetView link (since I don't have a personal picture going outbound) showing how it's setup so you can see what I'm talking about ( [3] ). In both of those cases, the "from", "to", & "via" would be needed as we don't want to penaltize the Inbound traffic since they never have to stop for a traffic light in both of those places. -James [1] - http://www.openstreetmap.org/browse/node/684666723 [2] - http://www.openstreetmap.org/browse/node/684666821 [3] - http://goo.gl/maps/E9gD8
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