2012/10/16 Chris Hill <o...@raggedred.net>: > Perhaps in your part of the world, but not everywhere. Crossing solid lines, > as centrelines or lane separators have exceptions for ordinary vehicles (not > just emergency vehicles) here. Yet another example of how local influences > must be applied to documentation. The page showing how highway types are > interpreted in different countries may be copied for such definitions.
yes, traffic rules are different in different areas, and someone offering routing should make himself familiar with local exceptions. This is even more an argument to keep straight definitions. If you map that there is no physical division but only a specific legal divider, this information will be available to those who interpret the data according to their rules, but if you treat all kind of divisions the same (separating the ways in OSM) routers will asume for everybody (pedestrians, emergency vehicles, bicycles) that there is no connection (unless you create these connections, either explicitly (connecting (foot?)ways) or conceptionally by creating a relation between the two). When you choose to split the ways and create a relation between the two, there will still remain some questions open. Actually you shouldn't tag them as highways then, but as lanes, so the question is how to deal with this. Would you make a) no highway at all and dataconsumers would need to take all lanes as well in account (or maybe get single highways from preprocessing) or they would have holes in their data. b) assign the highway-tag only to one of the ways (actually not working without introducing further "helper ways") c) assign a highway-tag anway to all these lanes and additionally state that they are lanes. d) do nothing of this and renounce from the details. Frankly I think that none of these alternatives with the relation is really nice. b) would probably be the easiest to introduce, because dataconsumers could in theory ignore the lanes and rely only on the highways, but practically you would have to continuously fix newly introduced holes in the graph, because of higher complexity. The divider tag (almost not in use) could solve the problem we have in countries where there is no exception for driveways on the opposite side, and in general it could make mapping easier because far less turn restrictions would be needed (if routers adopted this mapping style). cheers, Martin _______________________________________________ Tagging mailing list Tagging@openstreetmap.org http://lists.openstreetmap.org/listinfo/tagging
