Freeciv

Jacob Nevins wrote on gna.org about game effects that try to adapt to world size:

"But the measure of world size they use is quite crude: MAX. xsize/ysize are native coordinates, so for iso/hex topologies, they doesn't relate entirely obviously to distance-used-for-waste, and the maximum distance-for-waste can differ from this measure depending on the map's aspect ratio (I think).

Use a more refined measure, of the maximum distance two tiles can be apart on the map. (Halving for wrapping maps; if not desired this can be adjusted by the ruleset author.)"