[OSM-talk] Ditches

[Steve Bennett]

On Tue, Dec 15, 2009 at 2:47 PM, Anthony <osm at inbox.org> wrote:
> I tend to agree with you, but:
>
> http://wiki.openstreetmap.org/wiki/Image:IMG_6783.JPG
>
> Are both of those bridges layer=1?  At least the road one, and arguably
> both, are effectively at "ground level".
>
> Right now I have the ditch with no layer tag (this way it acts as a barrier
> to travel through the park at layer=0).  But it doesn't feel right putting
> the bridges at layer=1.

I think you're on the wrong track with this one. Layer=x is really
just a hack to solve certain routing and rendering issues. This isn't
a place where "feels right" comes into it, imho.

You can mark things that are flat on the ground as layer=4, or
layer=-2, it doesn't really matter. All that really matters is the
relative layers of other items that cross them or join with them
(maybe).

>So I've used barrier=entrance for the node where
> the way and the ditch cross.  For the part going under the road, I have

There shouldn't be a node. They don't join. The bridge goes over the
ditch. It doesn't touch it.

And there's no barrier=entrance either. Barrier=entrance would mean
that the ditch disappears for a bit, ie becomes ground that you can
walk across.

>From the wiki: "A hole in a linear barrier with no specific
construction that limits passing through."

Definitely not what's going on in either of those two photos - I see
"specific constructions".

> barrier=ditch, tunnel=yes.

You either have a tunnel or a bridge, not both. Well, maybe sometimes.
But not here.

> Which, I don't know, is the part I like the
> least.  But the ditch isn't really a ditch at the time it goes under the
> road.  It's more of a drain pipe.  Is there a tag for drain pipe?  (I'll
> check the wiki right after I hit send).

Also check my reply earlier.

Steve