Guenther Meyer wrote: > Am Thursday 21 May 2009 schrieb Lester Caine: >> Guenther Meyer wrote: >>>> So while discussing HOW the default speed for roads are calculated is >>>> important, can we not simply apply that speed without adding another >>>> layer of complexity? >>> I wouldn't do that, because it's a derived value depending on a lot of >>> things like road type, time of day, weekday, construction sites, ... >>> >>> ok, you might add this value additionally with a special tag, to give a >>> hint to routing applications. >> Why? maxspeed IS that tag > no! > maxspeed is the tag, that specifies a given speed limit, and is legally > defined. it is NOT some average speed value for a specific road. ALL roads have a defined maximum speed limit ... is this just a matter of 'conversion to english'? The fact that a road does not have a specific sign is not something that maxspeed is concerned with? At least in my reading of the guide lines on maxspeed.
>>> but there are more applications than just routing, to which that data >>> may be useless. >> Does that matter? >> maxspeed is already defined and exists >> Additionally there is a page for speed limits against highway tag and I >> remember a discussion about low speed limits in traffic calming areas >> which proposed an alternative to highway=residential for those areas, so >> the type of road is already included in defining the default maxspeed. >> >>> on the other hand the speed limits are defined values (at least in every >>> country I have been so far...). >> What I'm failing to see here is the REASON we need to add another set of >> area definitions simply to do with speed when that information is >> already well covered in existing tags - if they are used properly? >> > my first suggestion was exactly this: why not use and extend the already > existing tags for that, like "maxspeed = DE:in_town". > but after some discussion it was clear that such a tag would imply more than > just certain speed limits, as I already mentioned. that's why the idea of > using a more generic key was coming up. A key on a road segment is a lot more practical than defining another layer of complexity. And I can understand that maxspeed=DE:in_town makes a lot of sense since a global change to that limit does not require every way to be updated. There is a debate on changing the UK 60 limit to 50 which will need a lot of changes to these tags, but at present every road I go down seems to have had it's default limit lowered to 50 or even 40 anyway. Nearly got caught out with a new limit and speed camera last week :( So the next question has to be - because I'm not SEEING the reason - why is 'maxspeed=DE:in_town' a problem? What is it implying other than a fact of law? I would also point out that maxspeed needs a tidy up anyway since it does not have any provision for my previous note about VARIABLE speed limits. These are being applied more and more to UK motorways to cope with the congestion, and are changed based on traffic conditions. Roads in residential areas my also have lower limits during school days at start end end times. -- Lester Caine - G8HFL ----------------------------- Contact - http://lsces.co.uk/wiki/?page=contact L.S.Caine Electronic Services - http://lsces.co.uk EnquirySolve - http://enquirysolve.com/ Model Engineers Digital Workshop - http://medw.co.uk// Firebird - http://www.firebirdsql.org/index.php _______________________________________________ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
