[Tagging] bridge=humpback ?

[Christopher Hoess]

On Mon, Aug 11, 2014 at 5:33 PM, Richard Z. <ricoz.osm at gmail.com> wrote:

> On Mon, Aug 11, 2014 at 12:28:59PM -0400, Christopher Hoess wrote:
>
>
> > Maintaining both "bridge=movable" and "bridge:movable=*" has at least one
> > useful side effect, which I documented, for bridge geeks like me (i.e.,
> the
> > people who are probably going to be adding hyper-complicated bridge
> > detail); it lets you tag a formerly or planned movable span that is now
> > fixed in place with "bridge:movable=*" but not "bridge=movable". So you
> > could search for "bridge:movable=swing" and find both working and fixed
> > swing spans, but a router wouldn't treat the fixed ones as movable. (See
> > here http://en.wikipedia.org/wiki/1993_Big_Bayou_Canot_train_wreck for
> the
> > relevance of such spans.)
>
> This may be too subtle for many people and somewhat against the principle
> of least surprise.
>

Good point. I can easily see people "correcting" "bridge=yes" to
"bridge=movable" because they see the bridge:movable tag on a span. What if
we made "bridge=fixed" a synonym of "bridge=yes"?


>
> > bridge=covered has been mentioned now and before as possibly redundant to
> > "bridge=yes" and "covered=yes". I left it in because of this message:
> >  http://lists.openstreetmap.org/pipermail/tagging/2013-May/013546.html
> > <http://lists.openstreetmap.org/pipermail/tagging/2013-May/013546.html>
> which
> > suggested that a bridge covered over wasn't quite the same thing as a
> > covered bridge. I don't have a strong opinion on changing or keeping it
> at
> > this point.
>
> I would be in favor of keeping that one but the problem is - you can't have
> covered bridge=movable or aqueduct. I have seen covered aqueducts.


I don't think there are any extant covered movable bridges. Re. aqueducts,
in what sense was that "covered? A closed pipe? If we retain
"bridge=covered" in addition to "covered=yes", I think it should be
particular to the "classic" covered bridge where a truss (usually) has been
covered to keep out the weather.


> > As long as we're simplifying possible values in bridge=,
> > "bridge=low_water_crossing", which is somewhat established but a bit
> > awkward, could theoretically just be marked by a separate tag, maybe
> > "flood_prone=yes". The essential quality we're looking to convey is that
> > the bridge is engineered to spend some time underwater and come out
> intact.
>
> those can also look as culverts and it would be nice to have the same
> solution
> whether it is a bridge or a culvert. I have tagged those with
> tunnel=culvert
> and ford=yes


"flood_prone" might be a little better for both in that I think of a ford
as having water more or less perennially covering the crossing, whereas a
low water bridge, like a road dipping into an arroyo, is only covered by
irregular intervals of high water.

 Yours,

-- 
Chris
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