In Imperialism and Imperialism 2, a resource is a raw material or primary product obtained from the terrain of a city, depot, or port tile or one of the adjoining tiles (which number six except at map edges). the term includes raw materials (which can be processed into some other material) and other items such as horses.
- Coal (needing a miner to prepare for extraction)
- Iron (needing a miner to prepare for extraction)
- Meat (from cattle or fish)
- Oil (needing a driller to prepare for extraction)
Resources in the territory of a great power (i.e. a human or AI player) are wasted unless they are within the radius of a capital, or a depot linked by railroad to a capital (your own or a conquered one), or a port. Even there, they cannot be harvested unless there is transport for them. If all factors are in place, each unit of a resource adds to the stock in your warehouse every turn.
Resources in minor nations (including colonies) are harvested in mysterious ways, and for the extractive minerals often with no sign on the ground. Players have no control over them except to the limited extent applicable when a developer buys foreign land that contains resources other than food, and gets a share in the profits and can then send civilians in to improve the land.