[Tagging] what does maxheight=none mean?

[Ilpo Järvinen]

On Mon, 27 Oct 2014, moltonel 3x Combo wrote:

> On 27/10/2014, Martin Koppenhoefer <dieterdreist at gmail.com> wrote:
> > 2014-10-27 11:04 GMT+01:00 moltonel 3x Combo <moltonel at gmail.com>:
> >> The maxheight=* tag maps the physical limitation, not the sign (which
> >> can be absent or even wrong). Tagging maxheight=none really makes no
> >> sense.
> >
> > no, the maxheight tag maps the legal restriction (typically derived from a
> > sign, in absence of a sign might be implied by other legal provisions). For
> > physical restrictions use maxheight:physical (in some countries this is
> > even signed).
> 
> True; I was tempted to amend my sentence to note the physical/legal
> nuance, but decided against it for the sake of clarity. In most cases,
> physical and legal maxheight are pretty much the same.
> 
> My main point was that what is signposted on the bridge is just a
> "nice to have hint" from the mapper's point of view. What matters is
> the actual legal/physical limitation.

At least here in Finland the maxheight restriction sign [1] is posted 
occassionally significantly before the bridge without pre-warning distance 
extra sign [2]. In such a case the maxheight restriction applies from the 
sign onwards legally, so it really matters here also from the mapper's POV 
what the sign says. What's even more funny, I even noticed one place where 
this difference might affect routing (although the effect is quite limited):

  http://www.openstreetmap.org/node/1564470488#map=17/60.24009/24.95182


-- 
 i.

[1] http://commons.wikimedia.org/wiki/File:Finland_road_sign_342.svg
[2] http://commons.wikimedia.org/wiki/File:Finland_road_sign_815.svg