[Tilesathome] Extended Multipolygon support

[Frederik Ramm]

Hi,

Hermann Kraus wrote:
> I already noted this in a comment:
> # In theory each way could be represented as a multipolygon with the
> # following properties:

I saw this comment; I believe you wanted to say "each *closed* way"?

> I wrote this patch, so such ugly constructs are no longer needed and
> should be removed from our data. So it is counter-productive to add
> support for this "feature". 

If you define advanced multipolygons to allow this then it is no longer 
ugly but "specified behaviour" ;-) - but as I said, I'm not fond of 
touching rings either, it was someone else who stuffed that into the 
Wiki against my advice.

> I also would like to see the feature to handle
> old style multipolygons removed (inner and outer with the same tags) as  
> this would provide an incentive to change these polygons to the new tagging  
> scheme.

As map renderers, we have to educate mappers to do the right thing, but 
also we have to try to make the best maps from the material available. I 
think that removing support for old-style polygons would be premature. 
We should also try to get not too far out of touch with Mapnik. The 
thing I hate most about multipolygons is the idea that certain rings 
need to be clockwise or counter-clockwise. This pops up every so often 
and I always say it is rubbish and then people produce some strange 
example where it really makes a difference ;-) I hope we've now got rid 
of these cases once and for all.

Bye
Frederik

-- 
Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00'09" E008°23'33"