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

[Joerg Ostertag (OSM Munich/Germany)]

On Freitag 23 November 2007, you wrote:
> Hi,
>
> > Hmm? If the forest has the road as boundary it seems perfectly logical
> > that they share the same nodes. Another way of looking at it: if you
> > adjust the position of a node on the road, does this mean the boundary
> > of the forest needs to be adjusted. If yes, then they should be the
> > same node.
>
> I agree with that. Anything else would be an unneccessary editing
> nightmare if you're moving the road.

Sorry to disagree. 
But if you want to move both features at the same time. You simply have to 
select both features and then move them. As you would do in any other drawing 
application too. I can't see an editing nightmare with this.

It currently is a a little bit more into the direction drawing nightmare, if 
you want to separate these two feature, because someone was drawing the 
forest too near to the road. At least my known solution is to split the road 
once before and once after the offending node. Then delete the two segments 
in between. And then redraw this part of the road. The reconnect the 3 new 
Road Segments(sorry ways). This tends more to the classification editing 
nightmare to me. Especially if you have to do this for every 2nd or 3rd node 
on a longer road.
And it makes it even worse if some people do a good job in adding roads, but 
if they are near a forest they place one node 1 meter inside of the forest, 
the next one shares a node with the forest and the 3rd is 1 meter outside of 
the forest. This really doesn't sound like close to reality. I don't really 
like to steer into open wounds; but if you see things like this and have a 
look at the editor people seem to use; guess what ...

> It is, strictly speaking, true that the forest does not end at the
> road centreline but a few metres beside that - but we don't map both
> shoulders of the road, just the centreline, and *assume* that it will
> have a certain width, and in the very same way we can be asked to
> *assume* that the forest will end at one side of the road.

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. 
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.

-- 

Jörg (Germany, Munich)