Terrain (Civ4)

Terrain is "the physical features of a tract of land." In Civilization IV, each tile has one base terrain type, may or may not have hills, and may also have one or more terrain features. Together, these are the tile's terrain, and they are assumed to cover it uniformly. Terrain has a strong effect on the movement and combat of land units.

Features of water are also called terrain for our purposes, even though the English parallel to "terrain" would be "marine." Terrain also affects naval combat, although it is far less complex there.

Land Terrain

Base Terrain

There are five base land terrain types. All require 1 movement point to enter, and all gain 1 bonus commerce if next to a river.

Name		Template:Production		Special abilities
Grassland	2	0	0
Plains	1	1	0
Tundra	1	0	0
Desert	0	0	0	Improvements take 25% longer to build
Ice	0	0	0	Improvements take 50% longer to build

Rivers

Rivers are exceptional terrain in that they are not "in" or "on" a tile, but they run between tiles. A river is considered adjacent to all tiles that it runs along, including all four tiles which touch a place where the river bends or empties into water. Rivers supply fresh water to all adjacent tiles. A river adds +1 commerce to all adjacent land tiles, unless they also contain an unimproved forest or jungle. Only cities adjacent to rivers may build Levees.

Vertical Terrain

Hills are a sort of terrain feature, but they are not removable and thus in their own class. When a land tile has no hill, and is not a peak, it is flatland. See the Hill page for a bit more detail.

Name		Template:Production		Special abilities
Flatland	0	0	0	Can improve with Farm, Cottage, Workshop, Watermill Movement Cost: +0
Hill	-1	+1	0	Can improve with Mine, Windmill Movement Cost: +1 Sight distance: +1
Peak	-	-	-	Impassable

Terrain Features

Terrain features are considered removable by Civilization IV. Many can be removed by Workers, but all features are removed when you build a city. Thus, if you build a city on a floodplain, the floodplain is removed and only desert is left.

Name		Template:Production		Special abilities
Fallout	-3	-3	-3	+0.50 in nearby cities Cannot build improvements Movement Cost: +1
Floodplain	3	0	1	must be next to river must be in desert +0.40 in nearby cities
Forest	0	+1	0	Movement Cost: +1 +0.5 in nearby cities Defending units get +50% strength
Jungle	-1	0	0	Movement Cost: +1 +0.25 in nearby cities Defending units get +50% strength
Oasis	3	0	2	Source of fresh water Must be in desert Movement cost: 2 Cannot build cities or improvements

Water Terrain

Base Terrain

A lake is any body of water smaller than a particular size in tiles, which is moddable but normally 9 tiles. Even though all water tiles benefit from Lighthouses, being adjacent to a lake is not sufficient for a city to be coastal.

Name		Template:Production		Special abilities
Lake	2	0	2	Provides fresh water Defending units get +10% strength
Coast	1	0	2	Adjacent city is coastal Defending units get +10% strength
Ocean	1	0	1	Some naval units (Galleys, Triremes, Ironclads) cannot enter ocean except within a civ's cultural borders. Work Boats are not oceangoing until Astronomy.

Terrain Features

Ice is a feature of water, although unlike land features it cannot be removed.

Name		Template:Production		Special abilities
Ice	-	-	-	Impassable