[Tagging] Combining "locked=yes" with various access tags

[Greg Troxel]

Niels Elgaard Larsen <elgaard at agol.dk> writes:

> We have to accept that the tagging is never complete. And when
> surveying, it is often easier to tag "locked" than "access" (we can se
> the lock or try to open the gate but there are often no signs). So the
> tagging might reflect that we know that a gate is usually locked, but
> we do not know who can use the gate.
>
> At least "locked" should imply access=destination or private for
> routers.

I don't see it that why.  access=private, probably.  access=destination
means you can use a way if you decide to go someplace that you need to
use the way to get to.  But that's wrapped up with can you.

It's a little unclear to me what a "locked=no" gate is.  I'm guessing
it's a physical barrier than anyone can easily move out of the way.  So
arguably a barrier without locked shouldn't preclude routing, just a
2-minute delay.

Then there is 'access=' on the barrier.  This doesn't make a lot of
sense to me as in practice access is about the way, and the gate is
either:

  not locked, and not an impediment, but might keep cows in

  locked, and an enforcer of something that is alraedy true

or

  locked, and enforcing no travel when people have a legal right to do
  so.  Still, routers should not attempt to use this.


So maybe:

  foot=yes on a barrier=gate means that a person on foot can pass the
  gate (perhaps by walking around it) with minimal difficulty, such that
  the gate's presence should not affect routing

  barrier=gate locked=no (or no locked, default?) means that all modes
  may physically pass, with a mode-specific typical cost

  barrier=gate locked=yes means that all modes may not pass, unless
  there is a mode-specific foot=yes or bicycle=yes


The real problem is that locked refers to the ability to open the gate,
but many modes pass without opening, and we really care about "can this
mode actually traverse".   so locked=yes is a shorthand for all modes of
travel and we don't have a foot:can-walk-around=yes tag.   Until we deal
with that head on, this is going to be messy.

> According to the wiki, motor_vehicle=no means that motor vehicles are
> not allowed to travel through the barrier. The wiki does not say that
> having a key to the lock changes that.

agreed.


So we need three properties:

  legal right of access, perhaps only needed on ways

  physical ability to pass a gate

  is the gate locked, and if so which modes does that apply to