[OSM-talk] Validator Plugin (landuse=forrest+highway=xy)

Martijn van Oosterhout kleptog at gmail.com
Fri Nov 23 14:04:02 GMT 2007


On Nov 23, 2007 1:26 PM, Joerg Ostertag (OSM Munich/Germany)
<openstreetmap at ostertag.name> wrote:
> I thought we want to reflect the reality as good as possible. And the forest
> simply is not starting in the middle of the road. Only this way we increase
> the chance of later being able to use the data for other stuff than
> map-rendering.

It's totally obvious that the forest ends at the side of the road. A
road and a forest are mutually exclusive. Just like a road going
through a forest doesn't split the forest in two peices. It's obvious
that the part the we road is, the forest isn't. And yet, if some asks
you "are you in a forest" the answer is "yes" even though you are on a
road. So in a sense, the forest does extend onto the road itself.

> So if a renderer wants to really draw it really correct in low zoom, it would
> have to guess that if there is a railway he has to erase 2 meters of wrong
> drawn forest wood, if there is a highway primary he'll have to remove 6
> meters or maybe more ... and so on.  That sounds really wrong! So I would
> really encourage everyone to enter Data as close to reality as possible and
> not only draw for our current rendering engines which we know still have some
> way to go.

This is also incorrect. The model is layered. First come all the area
features, drawn so that features inside other features appear on top.
Then the linear features are given a width, which may or may not exact
metres, and drawn. Finally point features are drawn after having been
given a size. There is no guessing anywhere...

That said, you can do what you like. If I ever need to edit such an
area I'm not going to check if there are parks next to the road, I'm
going to expect that moving the nodes on the road is sufficient. If
according to the data I download the road and the forest are not
connected, then who am I to change it...

Have a nice day,
.--
Martijn van Oosterhout <kleptog at gmail.com> http://svana.org/kleptog/




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