On 28/06/2016 14:30, Greg Troxel wrote:
True, but in OSM it's currently at best awkward to have a complicated set of defaults, because then that information has to be encoded into all renderers and routers. We either need to have a single global default or to have some machine-readable specification of default values based on admin_level regions. Given that so many rules are different, and that we don't have enough explicit tagging, I think the machine-readable specification approach is the only workable one.
In OSM whenever there's been a choice between "making things harder for routers/renderers" or "making things harder for mappers" it's the former that tends to be chosen, because map consumers can at least automate what they do, and new mappers are hard to come by.
To take another example - should a router for GB assume that highway=track is public access, all other things being equal? I'd say that it depends - yes for Scotland, no for England and Wales. This has to be a decision taken by the data consumer since the wiki isn't much help, as http://wiki.openstreetmap.org/wiki/OSM_tags_for_routing/Access-Restrictions#United_Kingdom doesn't mention "track" and http://wiki.openstreetmap.org/wiki/United_Kingdom_Tagging_Guidelines is a bit of a pudding rewritten by someone who didn't really understand access rules. This means that data consumers need to come up with a "best guess" as to what mappers (most of which won't have ever read the wiki of course) actually meant.
It's the same for learner drivers - if it's going to give sensible advice, any router simply must have an understanding of local laws when it comes to edge cases like this.
Cheers, Andy _______________________________________________ Tagging mailing list [email protected] https://lists.openstreetmap.org/listinfo/tagging
