Hi, a) The thing is, if you don't tag maxspeed=50, then how do tell a residential road that is known to be maxspeed=50, against one that is just un-surveyed, and might be maxspeed=30,40 or 60?
c) source:maxspeed=sign is clearly correct if there is a sign. If you've surveyed around an area, and there isn't a sign, personally I'd tag source:maxspeed=survey. The alternative here, would be source:maxspeed=default or some such, but given our history of tagging "site unseen". It I think this is best avoided. Same goes for source=implied for the same reason. If you've visited and determined the speed limit, it is a survey. maxspeed=local_knowledge if you drive around the residential streets in your area all the time, and you just know they are all 50km/h. Just an aside, a simple case study in presumptions. Probably the most popular OSM open source router is OSRM. The speedprofiles for that project you can see here https://github.com/DennisOSRM/Project-OSRM/blob/master/speedprofile.ini I believe OSRM will use a maxspeed on a street if it finds one, so once you start marking maxspeeds it makes sense to mark others around them, otherwise a maxspeed=40 road will become a preferred road over other residentials and secondaries. I'm sure the motivation for tagging all residentials as maxspeed=50 was partly an attempt to address this issue. Of course, there is a good argument for this being fixed in OSRM, or in post-processing the AU data, etc. Ian. On 14 August 2012 15:30, Ben Johnson <tangarar...@gmail.com> wrote: > In regards to residential areas - I remember last year there was some talk > about the bot that added "50" with the (incorrect) "maxspeed:source" key = > "default residential speed limit in Australia" and I think there was > consensus in the local community that this was a mistake. > > With remapping some of my local areas, I'm now curious what's best > practice in Australia is for tagging maxspeed on residential streets. > Specifically... > > a) is it even necessary or desirable to explicitly define maxspeed for > every residential way - or should we just presume any highway=residential > is maxspeed=50, unless otherwise stated? > > b) if presumptions do exist, should 50 zones on tertiary and unclassified > ways be explictly tagged ? > > c) if tagging maxspeed on every street, in respect to source... does a > simple source:maxspeed=sign suffice for the "general area" or only for the > specific way on which the sign is placed? I notice these residential 50 > speed signs are often on tertiary streets, or gateway points into general > residential areas. Side-streets obviously share the 50 limit, but are > mostly not signposted. Do we need a new standard source value like > source:maxspeed=implied for the side streets ? > > Sorry if I'm re-covering old ground - I'm just not sure where it was > left... if anywhere! > > Thanks in advance.. BJ > > > ______________________________**_________________ > Talk-au mailing list > Talk-au@openstreetmap.org > http://lists.openstreetmap.**org/listinfo/talk-au<http://lists.openstreetmap.org/listinfo/talk-au> >
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