[OSM-talk] tagging roads

[Roy Wallace]

On Mon, Aug 3, 2009 at 10:23 PM, Martin Koppenhoefer
<dieterdreist at gmail.com> wrote:
> >>> Tag the width of the surface on which users of the way are expected to travel.
> >> I agree and would like to add: "and that is not constricted in the
> >> full usable height"
> >
> > I think the maxheight tag should be used here.
>
> This should include that above this surface (I would suggest up to 4,4
> meters or up to maxheight where available) there are no obstacles,
> because otherwise literally it is not complete.

Introducing 4,4 meters is arbitrary - don't like this idea. Maxheight
is already established for this purpose. You are right, though, that
if width=y and maxheight=x, it means there is a width of y metres with
at least x metres of clearance above the surface of the way.

> it's IMHO not about complication but about completeness. And it
> doesn't matter if the obstacle is large or small, it matters if is
> removable or not.

Width tag and maxheight tag gives completeness. You don't need to mix
the meaning of the two tags together.

> But why not put the width from line to shoulder, still paved, into the
> width-tag? You are not expected to use this, but you can do.

So you think the width should be defined by what "you can" use? That
is not good, because it depends who "you" are (e.g. car, bike,
pedestrian, in a wheelchair). I believe it is against the law in
Australia, for example, to drive outside the line markings. So "you
CAN'T" do this.

> actually I would consider the lines part of the lanes, not of the
> road. So I would see the width between the inner border of the lines
> as lanes:width (gets more complicated with different widths of the
> lanes, but this is a general problem in OSM: currently can't model
> lanes as they are).

Well, lines are part of the lanes, and lanes form the road. So the sum
of the widths of the lanes should be about equal to the width of the
road.

> This results in a hierarchical model:
> 1. entire road-construction, consisting of
> 2. paved road, shoulders, beam barrier, separators, bed, ....
> 3. the paved roads furthermore consistentent of
> different lanes
>
> where each level can have it's own tags for e.g. width, surface,
> maxspeed, maxheight, maxweight, access restrictions, etc. which would
> be inherited to the sublevels if there was not the same tag overriding
> it.

Sounds good to me. But if you want to keep it simple (which is usually
the case), I still stand by my definition of width of a way: "the
width of the surface on which users of the way are expected to
travel".