[Tagging] Extended tagging schema - my thoughts

Eckhart Wörner ewoerner at kde.org
Fri Aug 10 16:06:52 BST 2012


Hi Rob,

Am Freitag, 10. August 2012, 15:47:23 schrieb Rob Nickerson:
> p.s. To address some criticisms of my earlier proposal:
> 
> >Here are some disadvantages of merging everything into a single value:
> > - readability and ease of manual editing suffers
> 
> This suffers in any lenthy tag schema. Thr proposal is consistent so
> editors can be adapted to provide a fantastic GUI.

As written before, a "fantastic GUI" can be provided for every tagging scheme that is computer-readable. That does not invalidate the argument that competing proposals split the tagging into several key/value pairs to improve readability.

> > - you lose backward compatibility
> 
> The proposal falls back to existing tag schemas therefore providing
> backwards compatability.

No, it doesn't. If you set maxspeed=120; wet 80, then none of the existing routing programs can use this tag anymore. The Extended Conditions proposal uses the tagging maxspeed=120, maxspeed:wet=80, which allows existing routing programs to still use the maxspeed key.

> > - you run into the (real) risk of exceeding the 255 byte limit imposed on values
> 
> That would have to be one hell of a complicated access rule!!

Oh, you haven't seen anything. German inner city pedestrian zones are infamous for complex access restrictions (taking into account bicycles, delivery traffic, destination traffic, taxis, all of them depending on the day of week and the time of the day, and sometimes even on the direction).

Eckhart



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