[OSM-dev] A proposal for linking multiple ways into a virtual polygon

[Jon Burgess]

On Wed, 2007-05-16 at 02:59 -0700, Dan Moore wrote:
> > The only exception would be if the area was connected to some other way as well. 
> > This would be fairly rare I think. 
> 
> i guess things like administrative boundaries would be likely to share with neighbouring areas
> 
> 

My proposal would not handle that. A single way could only ever be part
of a single virtual polygon. If you want two neighbouring country
polygons to share a border then you would need 2 ways over the border
segments.

I think we need to discourage sharing ways around an areas otherwise we
get:

+-----+-----+
|     |     |
|  A  |  B  |
|     |     |
+-----+-----+

Is this 2 polygons A & B or is it 3 polygons, A, B and one which goes
around the outside of both A+B? 

Real examples with all European country boundaries would be way more
complex to work out.

	Jon