Quote Originally Posted by Blymurkla View Post
Why vornoi diagrams? Or, to put it another way, can you give an example of what you mean?
A Voronoi diagram is basically this field of dots where you have drawn lines that are halfway between any adjacent dots.

I thought it was more of a throwaway term than I guess it really is, but the underlying idea is that this is the major -thing- that nations do to establish regions and borders and such. Mapmaking was rather difficult way back when, so you'd get close enough and then just let some geographical feature, like the course of a river, serve as the actual line to demarcate your boundary, but if everything was flat, featureless farmland, then boundaries would look like Voronoi diagrams. There are various quirks that might mean a city's influence extends further than that of another, but your major provinces generally have a city located just about in the center (or on the edge in the case of coastal cities.)

Just because the food everyone was farming kind of flowed into whatever city they lived closest to, the borders of countries were largely based on who had control of what city, and thus armies don't really lay siege to villages or towns. In a war they want to occupy whatever cities, they need to clear out whatever local lord keeps running raids out of some nearby castle, and then they mostly move on to try and starve out the next location. This pattern makes rivers pull double duty as boundaries (though not the largest ones, as most cities are built on the large rivers,) because any reasonably equal army is going to hit you hard when you try to cross a river, and then after that the little squiggles and such are mostly due to mountain ranges and other impassable terrain. None of this is quite lined up with what the pure Voronoi diagram would be, but that's the general concept for how people decide that some parcel of land is part of Britanny, Provence, or France.

So... political maps that show all the regions within the nations.