From a brief look at the files it seems like you can put specific battlemap plans on resources and wonders but in some tests I have been unable to get it to work. The general idea is to make the game more realistic by having vinyard and farm battlemaps at points in the strategy map where the icons say they are. It also means that it is possible to fight over specific ruins that are not habitable enough to be towns in the game.
Does anyone know how to get this coded into the game?