terrain value changing possible?

[syneris]

I was wondering if it's possible to change the resources given by the different terrain. For example, make grasslands give only 1 food while tundra adds 2 production. Also, is it possible to add new types beyond food, coin, and production? Not more bonuses like iron or fish but like adding culture/research to basic terrain or something completely new.

 

[sir_woland]

Of course it is.

Assets/XML/Terrain/CIV4TerrainInfos.xml has an entry for each basic terrain type. The three iYield tags contain the resource values, the order being food, production and gold.

I suppose adding completely new yields to terrains could also be done, but it would require substantially more work and alterations.