[Tagging] Reviving the conditions debate

Eckhart Wörner ewoerner at kde.org
Wed Jun 13 15:00:52 BST 2012


Hi David,

Am Mittwoch, 13. Juni 2012, 14:47:09 schrieb aighes:
> I think your example: access:weight>5.5 = destination should be changed 
> into something like maxweight:destination=*. This seems to be more 
> logical and equal to your other examples.

First, I did not write the proposal, someone else did a long time ago. :-)
Second, in principle I fully agree with you, "destination" is a condition. Technically, the tag:
access:(weight>5.5)=destination
is equivalent to these two tags:
access:(weight>5.5)=no
access:(weight>5.5):destination=yes
However, "destination" as a value for access has been in use for quite some time, and I don't want to deprecate it (right now). The same goes for delivery, forestry, …

I have written down some lines on how to interpret "legacy" tagging in the comments.

> There is also an actual proposal: 
> http://wiki.openstreetmap.org/wiki/Proposed_features/Conditions_for_Restrictions

I've just learnt about this proposal, which is brand new. Most parts are the same, however, it has some new ideas I really don't like:
* It assumes access is the default, and e.g maxweight is a completely different beast. It isn't: maxweight=7.5 is just a shorter way of saying access:(weight>7.5)=no. (Again, I don't want to deprecate the maxweight key (right now).
* It invents new values, e.g. oneway[:…]=forward. The Extended Conditions proposal tries to invent as little as possible.
* It tries to incorporate the lanes proposal, and I'm not sure that's a good idea. Extended Conditions are certainly a necessary building block for lane dependent conditions, but that's a different story.

Eckhart



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