[OSM-talk-be] meerdere postcodes voor één gemeente

[Glenn Plas]

The advice below isn't correct.  We don't need alternatives, we need to
improve the postal_code boundaries to encompass those houses that are on
the wrong side of the postal code.

> That being said, using addr:postcode on boundary relations is rather uncommon practice.  Having another relation for Bellem with role=subarea and using addr:postcode on its administrative centre could be considered as an alternative.

Postal code's on administrative boundaries will throw a JOSM warning
when validating. I in fact delete those, they add no value to geocoding
at all, and will not be looked at.

However, in Flanders, we have almost a complete coverage in terms of
postal code boundaries.
https://wiki.openstreetmap.org/wiki/Tag:boundary%3Dpostal_code

There is still a lot of work in the rest of the country to complete
those, but they are perfect for handling border cases.   The AGIV/CRAB
tool also takes those into account, so if you mess up the postal code,
even though everything else is fine, you will see a 'error/wrong' on the
completion results. ( see http://aptum.bitless.be/ )

To see how complete this is, you can use overpass:

http://overpass-turbo.eu/s/qIO

Glenn