[mkgmap-dev] [PATCH v1] MP: Join tags by intersection and not by union

Thu Mar 25 19:12:51 GMT 2010

> In case multiple ways were joined to a polygon the polygon was tagged
> with the union set of tags of all joined ways. This algorithm is not
> compatible to the tag join algorithm described on the multipolygon
> relation definition
> (http://wiki.openstreetmap.org/wiki/Relation:multipolygon#Tagging).
>
> Additionally it can produce weired results. Example:
>
> MP, Tags: type=multipolygon (no more)
> Way 1, role=outer, Tags: boundary=administrative, highway=primary
> Way 2, role=outer, Tags: boundary=administrative
>
> The resulting polygon was tagged with
> boundary=administrative, highway=primary
>
> So a primary road was created around the complete region.
>
> The new algorithm creates a polygon with boundary=administrative only.
>
> WanMil
>

Did anyone test this patch?
I recommend to commit it because it fixes an incompatibility with the 
"official" definition of multipolygons.

WanMil