Matthias Julius wrote: > I don't. I think it follows the "principle of least surprise" better > if implied values don't change too much.
Great, then we should leave this as-is (implied oneway=yes for motorway_link) >If a highway is not oneway >by definition oneway=yes should not be implied. You do realize that "implies" means "if no value is specified, this should be the value that is understood", right? That the actual tags over-ride the implied value? So "the implied value could be incorrect some of the time" is no reason not to have an implied value. That's why it can be over-ridden by applying the appropriate tag. Having the implication is about reducing the effort required for someone to tag a motorway, and making it so that consumers of OSM data can make assumptions about the data. There are three options: 1. make no assumptions: This means every single motorway_link needs to have a oneway=yes or oneway=no (or oneway=-1). A pain for taggers, and doesn't help makers of routing applications who still need to handle the case where there is no oneway tag. 2. Assume oneway=no. This means that 95+% of motorway_links must be tagged. Still a pain for taggers. Makers of routing apps can't safely make this assumption anyway for fear of routing someone the wrong way up the motorway_link. It does mean that motorway_link has the same default as the other highways except for motorway though. 3. Assume oneway=yes. This means only 5-% of motorway_links must be tagged. It's the safe assumption that routers will have to make anyway. And of course it doesn't prevent anyone who wants to from explicitly specifying a oneway key/value for every motorway_link if they feel like it... Looking at the above, assuming oneway=yes seems the only way to go. Am I missing some big problem with it? > Trunk roads are > probably mostly oneway, too ... Off-topic. This is about motorway_link. -Alex Mauer "hawke" _______________________________________________ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
