[OSM-talk] administrative boundaries that run along roads - in the Mapnik layer

[Adrian Frith]

Hi All,

In Cape Town we've been mapping the suburb boundaries (which are
official) as boundary=administrative admin_level=10. These boundaries
run often down the middle of roads, railways or rivers. They show up
very nicely on the Osmarender/T at H layer as dashed red lines - see for
example
http://www.openstreetmap.org/?lat=-33.95&lon=18.45&zoom=12&layers=0BFT

On the Mapnik layer, however, they show up only where they do *not* run
along roads or railways - it seems that the other features are rendered
on top of the boundaries. Should we not be rendering administrative
boundaries above real features?

My understanding is that this would require a change to the z_order code
in osm2pgsql. Is that correct?

Regards,
Adrian