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

[bvh]

On Fri, Nov 23, 2007 at 01:26:32PM +0100, Joerg Ostertag (OSM Munich/Germany) wrote:
> I thought we want to reflect the reality as good as possible. And the forest 

Obviously, that is not the yardstick because then we would be tagging
roads as an area too. I can't speak for everyone, but I still
think mapping is the main purpose for openstreetmap. And a map is
by definition a stylized version of reality. (idem dito for routing)

> 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. 

I also don't think this is a valid argument. When such an application
arises it is a mechanical step to decouple the street from the forest
and offset the latter inwards for a certain amount.

> 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 

Yes that is really wrong, they just draw the street on top of the forest.

> 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.

I think the effort is counterproductive. Compare with a fysics experiment
where you use a handstopped watch and you know the your reaction time is
1 second. In that case when you stop your clock and it reads 17.45s
you write down in your report : 17s. Adding the extra digits is
wrong because you can't guarantee the accuracy of them: the 4 could just
as well be 3.

I feel the same way with this kind of information in openstreetmap :
at a certain point adding physical detail to the boundaries of
objects does not add any information (because the information is
inaccurate since your gps is generally at least a few meters of in a
forest, because the detail changes too much like next spring when
a new shoot roots just outside your border, or maybe because what
exactly is the border of a forest. Is a tree 5 meters out still part
of a forest, 3meters maybe, 1meter then?).

So instead of going for uninformational geographical detail, go for
valuable logical structure : ie explicitly show that the forest
is bordered by the street. And you can do this by reusing the nodes...

cu bart