[OSM-talk] [talk-au] maxheight/height

[Christoph Böhme]

Roy Wallace <waldo000000 at gmail.com> schrieb:

> On Tue, Jul 28, 2009 at 11:04 AM, Ross Scanlon<info at 4x4falcon.com>
> wrote:
> > Does this mean the bridge has a clearance of 2.8 or the road under
> > the bridge has a clearance of 2.8.  To me this would suggest the
> > bridge has a limit of 2.8 ie vehicles travelling over the bridge
> > can not be above 2.8 high.
> >
> > I'd suggest that if the bridge has a height limit, ie clearance,
> > then the bridge is tagged with max_height.
> >
> > If the road under the bridge has a height limit, ie clearance, then
> > the road is tagged.
> 
> Sorry, maybe this is a language issue. In my mind, "height limit" of a
> way refers to maximum height *above* the way, whereas "clearance" of a
> way infers maximum height *under* the way. Maybe "clearance" isn't the
> best word for this - please suggest others.

According to Wikipedia "clearance" [1] is the free space between a
vehicle and the structure (i.e. bridge) it is passing through. The
maximum height (and width) of the vehicle is -- at least for railways --
called "loading gauge" [2] while the dimensions of the structure are
called "structure gauge [3]. Thus, what we find on signs is the loading
gauge.

	Christoph

[1] http://en.wikipedia.org/wiki/Clearance
[2] http://en.wikipedia.org/wiki/Loading_gauge
[3] http://en.wikipedia.org/wiki/Structure_gauge