[OSM-talk] area_with_holes as alternative to multipolygon relation

[Martijn van Oosterhout]

On Tue, Mar 4, 2008 at 10:10 PM, Jon Burgess <jburgess777 at googlemail.com> wrote:
>  That is right. Looking from the outside these features may seem odd but
>  both were essential for the initial 0.5 multipolygon support.
>
>  The multipolygons created with the 0.5 API had no defined roles so there
>  was no way to know which was the outer ring during the initial XML
>  processing. Hence the solution to aggregate the tags of all the
>  constituent ways. Since the rules defined the holes had to
>  counter-clockwise they could not be used for other areas to the tags
>  should never clashed.

Ah. The logical way seemed to me to be to only take the tags from the
*outer* roles and ignore the tags on the inner roles. But if you
during the transistion couldn't tell inner from outer then you have a
problem.

Seems to me to call for a process to examine all the multipolygon
relations and assign inner/outer tags as appropriate... Then we can
fix the renderers...

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