[OSM-talk] Ditches

Steve Bennett stevagewp at gmail.com
Tue Dec 15 13:12:33 GMT 2009


On Tue, Dec 15, 2009 at 11:36 PM, John Smith <deltafoxtrot256 at gmail.com> wrote:
> Without layer information you'd be guessing if the road goes over the
> water or the water goes over the road, or the water and road are at
> the same level.
>
> You could come up with sane defaults,

That's the right thing to do.

> but that's making assumptions

Not if you document them. I agree that you can't leave everything up
to interpretation, but a road and a waterway crossing without a
junction is, by convention (and rather reasonably so), a road crossing
over the water. If nothing else, it's a far more frequent scenario
than continuously pouring across a public road, and there's a tag for
that.

> rather than tagging explicitly so you know beyond a reasonable doubt.

This isn't Law&Order. The whole tagging system is a means whereby
humans can store facts about the world efficiently, in order that they
can be used unambiguously by tools such as renderers. For that to
work, we need good documentation of what the tags mean, and how to
interpret them.

Steve




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