Terrain (Civ4)

Terrain is "the physical features of a tract of land."http://www.merriam-webster.com/dictionary/terrain 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. All land terrain tiles, with the exception of Ice, gain +1 bonus Commerce if adjacent to a river.
Terrain	Terrain 	 	 	 	Special abilities
 	Grassland	+2	0 	0	
*+1 adjacent to river
 	Plains 	+1	+1	0	
*+1 adjacent to river
 	Tundra 	+1	0 	0	
*+1 adjacent to river
*Improvements take 25% longer to build
*Cottages, Farms, and Workshops require fresh water
 	Desert 	0 	0 	0	
*+1 adjacent to river
*Improvements take 25% longer to build
*Cottages, Farms, and Workshops require fresh water
 	Ice 	0 	0 	0	
*Improvements take 50% longer to build
*Cottages, Farms, and Workshops require fresh water
=== 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. However, the two tiles which touch the source of a river and are behind it, with respect to the river's flow, are not riverside. 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 riverside Cities may build Levees, which provide +1 Production to every riverside tile within that City's radius.
=== 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.
Vertical Terrain	Vertical Terrain	 	 	 	Special abilities
 	Flatland 	0 	0 	0	
*Can improve with Farm, Cottage, Watermill, Workshop
*Movement Cost: +0
 	Hill 	-1	+1	0	
*Can improve with Cottage, 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.
Terrain Feature	Terrain Feature	 	 	 	Special abilities
 	Fallout 	-3	-3	-3	
*+0.50 in nearby cities
*Cannot build improvements
*Movement Cost: +1
 	Flood Plains 	+3	0 	0 	
*must be next to river, which will necessarily provide +1 
*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
*Negates +1 from rivers except with Lumbermill or Forest Preserve
 	Jungle 	-1	0 	0 	
*Movement Cost: +1
*+0.25 in nearby cities
*Defending units get +50% strength
*Negates +1 from rivers except with Forest Preserve
 	Oasis 	+3	0 	+2	
*Source of fresh water
*Must be in desert
*Movement cost: 2
*Cannot build cities or improvements
Note that when scrubbing (clearing) fallout from a tile, any surviving improvements and/or terrain features on that tile will be also removed, though some of the former may then be rebuilt afterwards. You will not be able to rebuild an improvement that requires a particular terrain feature that has been removed by the cleanup (or else already destroyed in the nuclear attack), e.g. a Lumbermill or Forest Preserve that had been placed on a now lost Forest.
== 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 the +1 from Lighthouses, being adjacent to a lake is not sufficient for a city to be coastal, which is required to build a Lighthouse.
Water Terrain	Water Terrain	 	 	 	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 exceptwithin 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.
Terrain Feature	Terrain Feature	 	 	 	Special abilities
 	Ice 	-	-	-	
*Impassable
== References ==
== See also ==
* Terrain in other games
Category:Civilization IV