[OSM-talk] Mapnik handling of highways that are also landuse...

[Dermot McNally]

2008/8/28 robin paulson <robin.paulson at gmail.com>:

> this sounds a lot like you're using the same way to form the centre of
> the road, and the boundary of the grass. wouldn't it be easier to use a
> separate way to represent each?

That is what I'm doing. I don't do this in all cases, but some do lend
themselves rather well to it. In my sample case, I have a closed way
representing a highway. So no, it wouldn't be "easier" to create a
brand new way, either reusing the nodes or staying just a little
within them. That's extra work. We can discuss whether your approach
(which is one I sometimes use) is more correct, but it certainly isn't
easier.

> i can't imagine the grass extends to the middle of the road

Clearly not - but I'd reiterate what Thomas said. Reuse of the way (or
creation of an identical one using the same nodes) is IMHO
topologically valid given the intended uses of our data. You would
only insist on modelling such green areas, say, 3m away from the road
centre if you were also in the business of mapping road boundary
instead of centre line. Mapping a centre line is an approximation to
reality. A simplified notion of abutting areas that assumes them to
extend to that centre line is entirely consistent with that
approximation.

Dermot

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