On Fri, Dec 4, 2009 at 4:28 PM, John Smith <deltafoxtrot...@gmail.com>wrote:

> 2009/12/4 Steve Bennett <stevag...@gmail.com>:
> > Again, this proposal is not primarily about rendering. That's a nice
> benefit
> > in some cases. The goals are:
> > 1) More appropriate data structure
>
> How is this more appropriate, you are loosing real world information
> to improve rendering.
>

The main focus is *adding* information to roads currently mapped as single
(non-divided) roads. Gaining information. Not losing. There are a huge
number of places that this will add information that was not previously
mapped.

I don't know how to convince you that I'm not proposing changing the way
major roads and dual carriageways are mapped. This is about minor divisions
in minor roads.

Let me ask you: how do you think that a road with a painted traffic island
down the middle should be mapped:
1) As a single road with no special tagging
2) As a single road with a tag indicating the division
3) As two separate ways, with ways connecting them every time there's a gap
in the painted division.

Here's an example that we can use to discuss (use satellite view):
*http://tinyurl.com/y8cxujs
**
*If you would like to propose some rules for the use of this tagging (like
don't use it for dual carriageways), that would be helpful.

> 2) Better usability

>
> How does this improve useability at all?
>

Because adding a single tag is a lot simpler than making two parallel ways.
Because modelling one road as is easier than modelling one road as two
roads.

> 3) Better rendering at no effort.
>
> Number 3 shouldn't be a goal, just like using the layer tag shouldn't
> be used to alter the rendering order.
>

Better rendering should always be a goal. What I think you mean is "we
shouldn't modify the way we map in order to compensate for some short-term
deficiency in current renderers". I agree. I think modelling minor streets
that have median strips as single roads is the right thing to do. Better
rendering is just an additional benefit. If there was a trade-off between
them, we would go with correct modelling.

Steve
_______________________________________________
talk mailing list
talk@openstreetmap.org
http://lists.openstreetmap.org/listinfo/talk

Reply via email to