On Tue, Dec 1, 2009 at 8:16 AM, Tobias Knerr <[email protected]> wrote: > Roy Wallace wrote: >> >>> Routing software that is aware of the local laws of each country seems >>> obvious. >> >> Um...what??? That will not write itself. Do you expect us to >> successfully digitize and maintain a database of all laws of all >> countries? In a wiki, even? That's ambitious! I'd prefer to stick to >> mapping what's on the ground. > > If we map what's on the ground, then we create a map database containing > "here is an oneway sign, over there is a cycleway sign". That's > nice, but if I want to do routing with this, I need information such as > "can I use way w in direction d with vehicle v?" - and in order to know > this, I need another database that tells me what a sign means in that > part of the world (for example: are pedestrians allowed to walk on ways > with a cycleway sign?). > > If we don't want a traffic law database, then we need to tag the > required information directly. But then mappers don't just map physical > reality. They interpret the signs (and other information) using their - > hopefully correct - knowledge of the laws. > > Both can work, but /someone/ has to do the transfer from reality to road > network attributes - either software (using a traffic laws DB) or humans > (mapping more than just what's on the ground).
Good points. You did find a flaw in my argument - that I was sort of advocating exhaustive tagging as well as only mapping what's on the ground. Funnily enough, I actually find both of these extremes acceptable. But that's not the point... The point I was making was that it should *not* be necessary to *require* "a database of all laws of all countries" to know what highway=cycleway means. There should be one definition that is consistent for the whole world. For example, "this path is marked with a sign with a bicycle symbol on it". If people also want to put in exhaustive information inferred from a law book, I'd prefer they go ahead and use "foot=no + source:foot=lawbook". If people prefer to leave out the inferred information, and instead write routers with country-specific defaults, that's cool, too. But highway=cycleway tags in the OSM database should all mean the same thing. _______________________________________________ talk mailing list [email protected] http://lists.openstreetmap.org/listinfo/talk
