Cities and Food

So, has anyone come up with a decent system to determine how much land it takes to support and feed a settlement? This would be very helpful when trying to ACKSify classic fantasy settings, like, for example, when trying to figure out how much territory a huge city like Waterdeep would have to control to support it's existence?

I'm out of reach of my books right now, but certainly, I can build these as regular domains, fitting the city into the scheme and seeing how big of a realm results (with the usual shifts for being centralized and urban, if that's what we're looking at). It's not really a proper city-state that comes out, I feel, though. I'd also like to have a quick way of seeing how trade would factor into this.

Any thoughts on this?



Alex was just waxing philosophical about this in the "Let's Read ACKs" commentary thread: