[OSM-talk] Highway tagging in general around the world

Dave Stubbs osm.list at randomjunk.co.uk
Wed Aug 15 11:48:30 BST 2007

On 15/08/07, Brent Easton <b.easton at exemail.com.au> wrote:
> >To pick up on the other thread, there is really no point in ref:au.
> >ref in Australia _means_ ref:au. By all means tag it as
> >is_in=Australia if you want to, but we'll eventually be able to infer
> >that from country boundaries anyway, and Australia's boundary is
> >pretty easy.
> Is this realistically going to happen in my lifetime? Do we have the entire world's country boundaries recorded to the required level of detail to be able to efficiently calculate which country any particular segment is in? Is it going to be able to cope with complex borders wrapping around sections of other countries?

Probably not, but you will be able to approximate -- it'll probably
need help from is_in style tags. ie: if I roughly draw round france,
say, "that's france!" (just for my renderer), then anything that
doesn't tell me where it is explicitly, use that bbox (well, maybe a
simple polygon) to guess. "Island" countries can be solved with some
judicious priority ordering of the simple polygons being checked.

With spending a bit of time on the tool chain, it wouldn't be that
difficult to set up something like this now (for very rough borders).
The OSM data itself is then being used to define the level of detail.
It's also something very easy for every mapper to fix, by adding the
necessary tags where the approximation is getting it wrong.

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