On the routing engine side these tags will be translated to turn penalties for specific turns, so the matching equivalent would probably be from,via,to relations. Which is not a feasible modelling in OSM realistically speaking. Simple stop signs could go on ways, but fail to capture more complex situations.
The problem with traffic lights specifically is their interconnectivity: you don't want to add turn penalties multiple times if traffic lights are connected. But you can't tell. This is a bit off-topic, feel free to cross-post to the osrm-talk or routing mailing list, or open an issue in osrm-backend. On Fri, Mar 17, 2017 at 3:29 PM, Tod Fitch <t...@fitchdesign.com> wrote: > From a data consumer point of view, what type of tagging would be > reasonable to indicate the, for lack of a better work, direction of travel > a stop, give way or traffic light has effect? > > On Mar 17, 2017, at 3:54 AM, Daniel Hofmann <hofm...@mapbox.com> wrote: > > Jumping in here to give a perspective from a routing engine (OSRM, > https://github.com/Project-OSRM/osrm-backend#open-source-routing-machine). > We do not handle direction tags on nodes which indicate a property for a > way or a turn at an intersection. The example with stop signs and give > yield signs is spot on. Even worse is the assumption that routing engines > can just infer the direction by checking the distance to the nearest > intersection. This is in conflict with how parsing and creating a graph > works. > > There is a similar problem with exit_to node tags, indicating the exit way > destination - you can read about it here > > - https://www.openstreetmap.org/user/daniel-j-h/diary/40555 (en) > - https://www.openstreetmap.org/user/daniel-j-h/diary/40554 (de) > > Cheers, > Daniel J H > > > On Fri, Mar 17, 2017 at 11:25 AM, Martin Koppenhoefer < > dieterdre...@gmail.com> wrote: > >> >> 2017-03-16 5:13 GMT+01:00 Tod Fitch <t...@fitchdesign.com>: >> >>> The “direction” tag [1] has different uses that seem disjoint to me. >>> >>> 1. To specify the orientation (compass point or degrees from north) >>> of an object (adit or cave entrance, etc.). >>> >>> >> "orientation" would have been a better descriptor IMHO, but the crowd >> uses this tag differently (see taginfo, also subtags like roof:orientation, >> ...). Direction is working for me nonetheless. >> >> >> 2. To specify direction (clockwise/counterclockwise) around a roundabout >>> (not sure why this is needed as it should be apparent from local laws or >>> specified with a “oneway=yes”). >> >> >> >> agree with you >> >> >> 3. To indicate the direction (forward/backward) a stop or yield (give >>> way) sign has effect along a way. >> >> >> >> broken. From time to time people are coming up with features to tag on >> nodes that require (or seem to require) the information of a direction. >> Taking the direction of a different object (e.g. here a way) doesn't seem a >> healthy way to represent this. Ways might get split, might get reversed, >> nodes might be (or become) part of several ways, etc. Either use a cardinal >> direction or a short way stub or a relation, etc., but not "forward" or >> "backward" tag values on a node, it simply doesn't make sense. Tags should >> refer to the object they are tagged on. >> >> >> >> >>> Oddly, that third use seems only for stop and yield signs but not for >>> traffic signals where a “traffic_signals:direction=forward | backward” >>> tag is to be used. However that seems to be the most used form [2]. >>> Apparently some have figured that if we have “traffic_signals:direction” >>> there should be “stop:direction” [3] and “give_way:direction” [4] tags. >>> >> >> >> similarly broken >> >> >> I would keep the variant 1 and discourage 2 and 3. >> >> Cheers, >> Martin >> >> >> >> _______________________________________________ >> Tagging mailing list >> Tagging@openstreetmap.org >> https://lists.openstreetmap.org/listinfo/tagging >> >> > _______________________________________________ > Tagging mailing list > Tagging@openstreetmap.org > https://lists.openstreetmap.org/listinfo/tagging > > > > _______________________________________________ > Tagging mailing list > Tagging@openstreetmap.org > https://lists.openstreetmap.org/listinfo/tagging > >
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