[talk-au] How to make admin boundaries disappear if they aren't duplicated with highway=* etc

[John Smith]

For those wanting to de-merge other way information from admin
boundaries here's a cheat sheet, firstly setup and test your filter
settings, for this purpose I setup 2 filters, one to disable or hide
waterways and coastlines even if they are admin boundaries as I see
these as harmless compared to other sorts of ways. I also setup a
filter to only show admin boundaries with railway or highway tags, as
these are the most common that need to be fixed:

filter 1: waterway=* | natural=coastline | natural=land
filter 2: boundary=administrative -(highway=* | railway=*) type:way

You need filters in that order, I also selected the hide option so all
the irrelevant boundaries just don't show.

Next you can use the XAPI interface to download all the admin
boundaries within a given bounding box by opening a location from
within JOSM:

http://xapi.openstreetmap.org/api/0.6/way%5Bboundary=administrative%5D%5Bbbox=151.72119139999998,-28.4638623,153.62731929999998,-26.6670958%5D

The bbox above is for south east queensland and will download about
33M of OSM data as a result, but the same thing could be used for
anywhere.

With the filtering in place there should be only a few admin
boundaries still being displayed, all you need to do then is copy and
paste or duplicate the ways, slightly offset the boundaries and you're
done.

The XAPI interface is delayed by 5 minutes or so behind the main API
server, so it can be worth selecting any/all ways and update them from
the main API before editing.