On Wed, 22 Jul 2009, Nicholas Barnes wrote: > Should, for example, the component ways making up the roundabout be > grouped in their own "I'm a roundabout" relationship?
Do we need to be able to tell which ways are part of a roundabout anyway? I mean, on the ground a roundabout is just a one-way circular road with some other roads coming off it - there isn't really anything special about it that makes it a roundabout. The only use of an explicit "I'm a roundabout" tag/relation that I can immediately think of is to make driving directions more human-readable (i.e. "At roundabout, take the 3rd exit"). In this case it may be better for the data user to use some heuristic, much as we do ourselves when we look at a piece of road. e.g. If there is a closed (clockwise in the UK) one-way loop with a diameter of less than X metres then consider it a roundabout when generating human-readable driving directions. Using this kind of heuristic would also have the advantage of setting an application-specific upper bound to the size of a roundabout - when roundabouts get beyond a certain size then it is probably better for sat-navs to go back to the usual "take the next left" driving directions instead of "take the 7th exit". - Steve xmpp:st...@nexusuk.org sip:st...@nexusuk.org http://www.nexusuk.org/ Servatis a periculum, servatis a maleficum - Whisper, Evanescence _______________________________________________ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb