On Tuesday 14 October 2008, Stefan Monnier wrote: > > Tagging a road as something implies certain rules, surely, and only > > when those rules are different from the standard (for that country) > > should you need to say so. Same as the oneway=no discussion that > > went on previously. > > All those discussions about cycleways, motorway_link, maxspeed, > etc... seem to point at the same problem: on the one hand, the > authors should need to enter as little info as possible, and as close > to the "on the ground data" as possible, which means that it should > elide all the data that's available from context (local laws and > customs); and on the other hand, users of the data want it to be in a > much more regular form, without having to worry about the customs > used in any particular part of the world. > > So, I think we should split the data in the following way: > 1 - the user-written data, as close as possible to what's available > on the ground. > 2 - a bunch of "locales", defined by the land they cover (typically > countries, states, provinces, ...). > 3 - a set of rules that say how to interpret the raw data for > specific locales. > 4 - A library that takes the above 3 and generates a "clean" output, > indendent from any local laws and customs.
I think I've been mentioning a thing like this for quite some time now. Things we need would be: * a set of "common tags" that could be used all over the world, but allow countries to discard/introduce some. This is mainly to not have different tags for the same thing in each country. This should be done for things like ** vehicle types ** special highway types (although I guess it's best to do that with a new highway_type tag for now) * a formally defined access structure, without any possible ambiguity. I tried starting this for quite some time now: http://wiki.openstreetmap.org/index.php/Proposed_features/Access_restrictions with unambiguously defined rules to parse them. * a default set of rules that map "tags" to that structure, and additional sets for each country (or smaller region if necessary) that can override that default set of rules. ** By "tags" I mean anything from highway=cycleway to access=destination, or additional tags like highway_type=pedestrian_zone. I understand some don't like country specific rules, but I think this is much better than translating each and every traffic sign to the full list of access rules which will always introduce problems when a country changes some specific traffic rules for those signs. Just like you wouldn't tag the default maximum speed. Ben _______________________________________________ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
