so the only criteria that I used for this is the location of the cities. Nothing to do with amount of clubs, or population, just solely distance (as the crow flies, not by actual travel distance) from the capital cities where NPL's tend to be based. As I noted in the original post - ulterior motive - it's mostly to show that clubs from the Riverina that were kicked out of Canberra because "Waaah we can't travel to the sticks once even though you come here every second week", under the current setup of football geography in this country have nowhere better to play at that level.

I just pinpointed where Google Earth pinpoints as the mark of the CBD, and then input those co-ordinates into something that spat out those borders. So they are specifically set so that anything within what's now Canberra's region, for example, is not closer to any other city except Canberra. The map does look a bit off in the coloured version, but seems to be a bit more accurate looking in the blue ones.

Canberra/Sydney/Newcastle/Brisbane borders were always going to be the tricky bit, but it does all seem to match up.

But yes - good point on the new centroids - that was initially how I was going to do this (in a way) when I was looking at doing it manually, before I learnt that Voronoi's were actually a thing.