[OSM-dev] shp2multipolygon

[Anthony]

Does anyone have code to do shapefile to multipolygon (in
.osm/.pbf/.o5c format)?  What I want is to take a shapefile with
overlapping boundaries (e.g.
http://wiki.sharedmap.org/wiki/File:Qgis.png) and convert it into a
bunch of multipolygons with shared ways.

I used to have code to do this:
http://wiki.openstreetmap.org/wiki/User:%E2%A0%A0%E2%A0%81%E2%A0%9D%E2%A0%9E%E2%A0%93%E2%A0%95%E2%A0%9D%E2%A0%BD/SQL
and http://wiki.openstreetmap.org/wiki/User:%E2%A0%A0%E2%A0%81%E2%A0%9D%E2%A0%9E%E2%A0%93%E2%A0%95%E2%A0%9D%E2%A0%BD/Perl

But I didn't document it well enough and I forget how it works :).
And John is having a problem with it in that it only seems to work
when interior ways are exactly two nodes.

My understanding is that, as of about a year ago, none of the shp2osm
programs support multipolygons.  Hopefully this has changed.