Terrain.mp2c

Quick Jumps: 
* Terrain Chart
* Terrain Modification Flowchart 
====World====
The World Map is made of tiles. Each tile has a terrain type. The east and west map edges connect, making a cylindrical map that can be circumnavigated. 
===Terrain===
Terrain types affect 3 game elements: (1) Unit combat, (2) Unit movement, (3) Resources for cities. Each is discussed below:
====Unit Combat====
Terrain can sometimes affect combat. When a land unit is attacked, its defense strength is multiplied by the bonus of the terrain. Air and Sea units get no terrain bonus. See the page on combat for details, and the Terrain chart below for which terrains offer bonuses. (Rivers give an extra bonus of +50%.) 
====Unit Movement====
Sea and air units always use one movement point to move one tile. Terrain only influences the movement speed of land units. 
Land units - movement "speed":
*Easy terrain costs one move point per tile. Rough terrain costs more. The Terrain chart shows the move cost for all terrain types.
*Land units spend ⅓ movement per tile along rivers and roads, as long as the tile they are leaving has a connected river or road.
*Tribesmen, Explorers, Partisans, and Alpine Troops are outdoorsmen who move light and quick over terrain. For these units, it is like every tile had a road on it. Moving one tile costs always costs only ⅓ move point.
*With Railroad technology, roads can be upgraded to railroads. Units using railroads use only ⅑ move (3× faster than roads and 9× faster than roadless terrain.) Beware! Roads and railroads can also help enemy armies. Enemy units travel your roads at the same speed as your units. However, enemy railways can only be used as roads: units travel at 3× speed on non-allied railways.
* With Superconductors technology, you may build MagLevs (Magnetic Levitation rails). MagLevs allow units to travel with unlimited movement points.
*Before the founding of your first city, all units enjoy a +⅓ movement bonus. Nomadic tribes have greater fitness prior to sedentary culture. On the turn after your first city is founded, this bonus is permanently lost.
Cities always have roads inside. If a nation has the geographic and technological requirements, cities will also contain Bridges, Railroads, Quays, and Canals. The list of Terrain Improvements below has more info on these.
====Resources for Cities====
Cities may be built on any terrain except Ocean or Arctic.
Tiles within range of a city may be worked by the city's citizens. When a city works a tile, it receives three types of income: food, production, and trade. Tile Output is conventionally written as Food/Production/Trade. For example, "1/2/3" is a tile that produces 1 food, 2 shields, and 3 trade. In Freeciv, a production point is called a Shield.
Terrain sometimes has a Special Resource which boosts food, shields, or trade. For example, a Pheasant is a special Forest resource that increases a tile's food output. 
Terrain Transformation makes resources inaccessible. For instance, if a Forest with a Pheasant is chopped down, the Forest transforms to Plains and loses the Pheasant's food bonus. Exception: Changing Arctic terrain to Desert preserves the resource Oil because Oil.it is valid on both terrain types.
Note: In MP2-Caravel, more special resources are put on the map on Turn 2, in order to make a more fair and equitable geographic resource distribution. This may provide extra incentive to preserve the move bonus before the founding of your first city, to explore further and decide on Turn 2 where to put your first city. Extra resources which may appear on Turn 2 are: Berries, Spice, Peat, Oasis, Rubber, Gems, Elk, Furs, Ivory, and Iron. The other types are generated on the map before the game begins.
The Terrain chart below lists the output of each terrain, both with and without special resources.
==== Tile Corruption====
In Despotism and Anarchy, tile corruption gives output penalties. Any tile producing 3 or more of a given output, gets a penalty of -1 due to tile corruption. For example, unirrigated Grassland gives 2 food, and irrigated Grassland gives 3 food. However, if you're in Despotism, irrigated Grassland would produce 3-1 = 2 food. (This means irrigating Grassland in Despotism is wasted work, unless it's needed to make another adjacent tile able to be irrigated.) There are several ways to reduce or even eliminate tile corruption:
* For cities size 3 or more, celebration eliminates tile corruption, as does having Angkor Wat in your nation.
* For an individual city, building a Courthouse, The Sphinx, or Chand Baori.
* Supreme Court, Code of Hammurabi, or Mausoleum of Mausolos in your nation will eliminate or reduce tile corruption.
===Terrain Improvements===
Building a Mine, Road, or Irrigation can be done by Workers, Settlers, Founders, Engineers, and Proletarians to improve terrain. Transforming is an action that only Engineers can perform. Some types of military units can also do limited types of terrain improvement--these types are separately listed in the Unit Catalogue. 
Workers, Settlers, Engineers, and Proletarians can "irrigate" to produce more food, cut a Forest, or drain a Swamp. They can "mine" to yield more production points, plant a Forest, or create a Swamp.
Irrigation and Mines can't co-exist on the same tile. Once built, a mine or irrigation system will replace the other. 
A Mine can be put on Hills, Mountains, or Desert. Mining desert makes an Oil Well--it requires Construction technology. The Terrain Chart below shows the increased production yield. 
To irrigate land, the player must have a water source in one of the four cardinally adjacent tiles. Water sources are Oceans, Lakes, Rivers, Canals, or any other irrigated land. While city tiles get a free irrigation bonus, they don't count as a water source unless one manually irrigates them, or unless one has the Chand Baori wonder.
Terrain can be transformed to a new type of terrain. Attempting to irrigate a Forest, for example, creates Plains. (See "Terrain Modification Flowchart" below.) You cannot plant a Forest or "grow Hills" under a city's tile. 
Roads, Bridges, Quays, Canals, Railroads, and MagLevs can be built on the same tile as other improvements (such as irrigation). Roads and Rivers enhance trade for some types of terrain, and Railroads increase the production output of a tile by +50% (rounded down.) Quays, Canals, and MagLevs provide movement benefits but not output benefits. Roads, Railroads, MagLevs, and Canals can be made while worker-types are transported, except if inside Foreign territory. 
A Quay is an improvement on Rivers and Canals that 1) facilitates off-loading passenger cargo from transport units, 2) is a ferry infrastructure for crossing rivers. Quays connect to nearby Roads. The Quay itself is considered as a road type. Stepping onto a Quay tile takes 1 move point. Stepping out behaves the same as moving from a road to an adjacent road. Like Bridges, Canals, and Railroads, cities with the required geography will automatically get Quays after you discover the required technology.
* Ships can Unload (T) in a Quay, and Passenger cargo can Deboard (T) on a Quay. Units must offload in Quay in one of these two ways, in order to use adjacent Roads with no disembarkation movement penalty.
Moves Needed to Cross a River	Moves Needed to Cross a River	Moves Needed to Cross a River
No bridge, no quay 	2.00 	6/3
Quay adjacent to road 	1.33 	4/3
Bridge adjacent to road 	0.67 	2/3
A Sea Bridge can be built over Lakes and Oceans after researching Steel. Workers or Engineers must be inside a transporter ship over the desired tile, in order to make it. A Sea Bridge acts exactly like a Road and will connect to any Roads on the mainland. It must be built cardinally adjacent to a Land tile. Sea Bridges allow land traffic to move over and allow sea traffic to go through. (Land and sea units can co-exist on a tile with a Sea Bridge.) Sea Bridges automatically contain a basic Road, and they can also be upgraded: Railroads and MagLevs may be built on top of it. 
Road-type Terrain Improvements
Road-type 	Move
Cost 	Tech Req. 	Geographic Req.
Road 	⅓ 	None 	Land
Quay 	1 in, ⅓ out	Pottery 	River
Bridge 	⅓ 	Bridge Building	River
Canal 	1 	Engineering 	Adjacency to Ocean, River, or Canal adjacent to Ocean
Railroad 	⅑ 	Railroad 	Road on tile
Sea Bridge	⅓ 	Steel 	Ocean or Lake cardinally adjacent to Land.
MagLev 	0 	Superconductors	None
====Military terrain improvements====
frame|right|Buoy and its vision|link=https://freeciv.wikia.com/wiki/File:Buoy-vision.PNG|135x135px
There are 9 kinds of military terrain improvements. Each requires a technology.
*A Hideout can be made in Forests, Swamps, Mountains, and Jungle, but not in someone else’s territory. Units in a Hideout are invisible to other players. Only Foot soldiers alone can make Hideouts. Only Land units and Helicopter types can hide in them. Other units will be seen. Hideouts are undetected on the map, and invisible to anyone not inside them. Units inside will display an icon to indicate they are in a Hideout. To summarize, the only way to see a Hideout is to have a unit inside it: therefore, it's important to remember your Hideouts if you do not occupy them. A Hideout utilizes natural terrain and foliage; therefore, for each turn it is unoccupied, a Hideout has a 15% chance of being lost to weather or other forces of nature. Hideouts require Warrior Code technology. Hideouts can't co-exist with other base types. The hot-key to make a hideout is shift-H.
*Forts are quickly improvised terrain improvements that increase defense and provide an outpost presence. Enemies can only kill units in a Fort one at a time, instead of all at once. Against Land, Missile, and Sea units, defenders get a 1.33× defense bonus. (The exception is Aircraft and Armor, which ignore the defense bonus.) Whether occupied or not, a Fort provides free vision on every adjacent tile and 2 tiles out in the cardinal directions. This makes Forts useful for border watch security. Forts do not claim national territory, but they allow a Settler to claim the tile to build a city. Forts require Masonry tech. The hot-key to make a Fort is shift-F.
*A Fortress can be built on any tile that already has a Fort. Enemies can only kill units in a Fortress one at a time, instead of all at once. A Fortress gives Land units a 2× defense against all Missile, Sea, and Land units. Unlike the Fort, the Fortress also gives Land units a 1.67× defense against Helicopters, Armor, and Air units. Armor II is the only unit against which Land units get no defense bonus from a Fortress. Fortresses claim and extend national borders. Once Invention is discovered, units in a Fortress have increased vision. Fortresses require Construction tech. The hot-key to make a Fortress is shift-F.
*A Castle can be built on tiles that already have a Fortress. Castles get the same defense bonuses as a Fortress, except for one difference: the Castle is immune to attacks from the Siege Ram unit. Also, Castles have greater vision, claim more territory, and hide the units inside, making them unseen to enemies. Castles require Construction and Feudalism. Castles can't be built after you discover Gunpowder tech. The hot-key to make a Castle is shift-F. Castles are a major construction project that take 5½ worker-turns to build.
*A Bunker can be built on a tile that already has a Fortress. It has the same defense bonuses as a Fortress. However, unlike the Fortress, enemies can't see units inside a Bunker, and it is immune to attacks from Air and Missile units (except Nukes.) Bunkers require subterranean construction and take 18 worker-turns to complete. They neither claim as much land nor see as far as a Fortress. Bunkers require Steel technology. The hot-key to make a Bunker is shift-F. Bunkers cannot be pillaged. Removing one is a longer operation which takes 2½ worker-turns. You must dismantle it to the original Fortress it was built upon, by doing the Remove Bunker command (shift-F).
*In an Airbase, units are not subject to Stack-Kill, but Air units become open to attacks by Land units. Air and Helicopters may land and refuel. Paratroopers can be launched from Airbases. Airbases can't be made by Settlers. The hot-key to make an Airbase is shift-E.
*Radar installations extend Airbase vision distance by \sqrt30tiles. They can be built inside an Airbase in 2½ worker-turns. The hot-key to make Radar is shift-E.
*Buoys are made by Workers or Engineers on board a ship on Oceanic terrain. Buoys give permanent vision of surrounding tiles. A chain of Buoys can give early warning for sea traffic or amphibious invasions. They can be pillaged by all warships from Ironclad onward. The hot-key to make a Buoy is shift-F. Buoys can see cardinally adjacent Submarines.
*A Naval Base is a Fortress which gives refuge for Sea units to heal with a defense bonus and without the threat of kill-stack or the "Pearl Harbor effect." In straight cardinal directions, they can see Submarines at a distance of 2 tiles. Enemies can only kill units in a one at a time. Requirements are Engineering, Low-land terrain, and a tile cardinally adjacent to Ocean.
*Bookmark the page on Bases to reference full details for every type of Base.
*Terrain and Base defense bonuses multiply together. Bookmark this chart for reference.
==== Advanced Tile Improvements ====
After Refrigeration has been discovered, irrigated tiles can be irrigated one more time to make Farmland. This increases tile food production by +100% if the city working it has a Supermarket.
Only engineers can directly Transform land (hotkey: "O"). (See Terrain Modification Flowchart below.)
*For transforming Swamp to Ocean, one of the eight adjacent tiles must be Ocean already.
*To transform Ocean into Swamp at least 2 of 8 adjacent tiles must be land. To work on Ocean, Engineers must be on a transport. The new Swamp tile will get a River if built adjacent to a river tile's single mouth.
Engineers work at 2× speed, performing 2 worker-turns on tile improvements each turn. They complete all improvements in half the time specified in the Terrain Modification Flowchart and Terrain Chart.
Two or more units working on the same tile under the same orders combine their labor, speeding completion of their project. Be careful: when a unit's working orders are interrupted, its progress is lost. Units may join a multi-turn improvement project midway through it to contribute their work. For example, if a project takes 5 turns and is worked by a single worker, a worker joining the project on the second turn will split the 4 remaining worker-turns with the other worker, and they'd both finish in two turns. However, it is important to remember: for a unit to get credit at turn-change for work that it begins, it must have MORE than 0 moves left. 
🡲 Any special resource on a tile is lost after its terrain type is transformed to a different terrain type. It reappears if the tile is transformed back to its original terrain. 
=== Huts ===
Huts are primitive villages spread across the world at the beginning of the game. Any land unit can enter a village. When the village is entered by a land unit, you get a random bonus. The bonus may be a small amount of gold or bulbs, or a defensive military foot unit equal to your current technological level. (If you have Bronze Working, you may get a Phalanx!) After entering a village, it disappears.
Huts encourage you to explore the game at the dawn of time, to collect the bonuses of learning from the world and other tribes -- before someone else does!
NOTE: Huts are an optional game setting that can be turned off. 
===Rivers===
Rivers increase movement the same as Roads while giving a +50% defense bonus. Roads can't be placed over river tiles until Bridge Building is discovered. A tile with a River gives the same trade bonus as a tile with a Road. On Grassland, Plains, Tundra, and Desert, a tile with a Bridge will give an extra +1 trade. On other terrain, Roads and Bridges give no trade bonus. 
====Canals (changed in MP2-Caravel, read carefully)====
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Canals are terrain improvements that allow ships to pass. Build-time is 5 worker-turns, the same as a Mine. Like Rivers, they can be used for irrigation, but they give no trade bonus and no move bonus. After researching Engineering, you can build Canals with Settlers, Workers, Engineers, or Proletarians. Canals require a water source: a cardinally adjacent River, Lake, or Ocean. A Waterway is a special type of inland Canal that can extend your Canal's length; these can be built cardinally adjacent to any Canal. You can also build longer Canals by transforming land to Lake or Ocean, in order to provide the needed water source. See Terrain Modification Flowchart, below.
====Appearing Resources====
* Turn 2 resources. When the map is generated, special resources are randomly dispersed at game start but also on Turn 2. MP2-Caravel automatically disperses a few more resources on Turn 2 in order to create a fair statistical distribution of special resources. Making cities on Turn 1 will give you one more turn of production, but you can't see the resources which will appear at the start of Turn 2. Because these resources are for statistically balancing the terrain, only some types of resource appear on Turn 2: Berries, Spice, Peat, Oasis, Rubber, Gems, Elk, Furs, Ivory, and Iron.
* Wild Game. From Turn 2 until Turn 20, plentiful Deer and Wild Boars wander the early earth. Each is a resource giving +2 food to its tile, if worked by a city. Because these resources wander, be attentive to make your city adjust to their arrival and departure: The only thing worse than missing the opportunity for the food bonus, is to continue working a sub-optimal tile because you did not notice the wild game has left a tile you're working!! Wild Game simulates the gradual transition from Hunter-Gatherer to fully Agricultural societies. It also helps propel multiplayer games out of a prehistoric phase slowed by the fact you can't repeatedly hit "Turn Done" in multiplayer games with fixed-length turns.
===Terrain Chart===
Terrain 	F/P/T	Special 1	F/P/T 	Special 2 	F/P/T 	Move cost•Defence	
Result:
Irrigate(turns)Mine(turns)	
Result:Road (turns)Transform (turns)
Deep ocean	1/0/2	  	 	  	 	1M
1× 	✘✘ 	✘✘
Desert 	0/1/0	Oasis ‡ 	3/1/0 	Oil 	0/4/0 	1M1× 	+1F (2½)+1P*** (2½) 	+1T (1)Plains (12)
 	 	River † 	0/1/1 	 	 	 	+2F (2½)+3F† (2½) 	
Forest 	1/2/0	Pheasant 	3/2/0 	Silk 	1/2/3 	2M
1.33× 	Plains (2½)Swamp (7½) 	+0T (2)Grassland (12)
 	 	Berries 	2/2/2 	Wild Boar **	4/2/0 	 	 	
Grassland 	2/0/0	Resources	2/1/0 	Deer ** 	5/0/0 	1M1× 	+1F (2½)Forest (5) 	+1T (1)Hills (15)
Hills 	1/0/0	Coal 	1/2/0 	Wine 	1/0/4 	2M2× 	+1F (5)+3P (5) 	+0T (2)Plains (12)
Jungle 	1/1/0	Gems 	1/1/5 	Fruit 	5/1/2 	2M1.5× 	Grassland (4)Forest (5) 	+0T (2)Plains (6)
 	 	Rubber 	1/3/2 	 	 	 	 	
Lake 	1/0/2	Fish 	3/0/2 	  	 	1M1× 	✘✘ 	✘Swamp (18)
Mountains 	0/1/0	Gold 	0/1/8 	Iron 	0/4/0 	3M3× 	✘+1P (5) 	+0T (3)Hills (12)
Ocean 	1/0/2	Fish 	3/0/2 	Whales 	2/1/2 	1M1× 	✘✘ 	✘Swamp (18)
Plains 	1/1/0	Buffalo 	1/3/0 	Wheat 	3/1/0 	1M1× 	+1F (3)Forest (8) 	+1T (1)Grassland (12)
Swamp 	1/0/0	Peat 	1/4/0 	Spice 	3/0/4 	2M1.33× 	Grassland (6½)Forest (6½)	+0T (2)Ocean (6)
Tundra 	1/0/0	Elk 	3/2/0 	Furs 	2/1/3 	1M1× 	+1F (2½)Desert (7½) 	+1T (1)Plains (12)
 	 	Gold 	1/0/8 	 	 	 	 	
Arctic 	0/0/0	Ivory 	1/1/4 	Oil 	0/3/0 	2M1× 	Tundra (7½) +3P (5) 	+0T (2)Desert (12)
 	 	Furs 	2/1/3 	 	 	 	 	
land tiles 	 	 	 	 	 	 	farmland: +100%F 	railroad: +50%P
(rounded down)
* Note: Terrain change time is given in worker-turns. Engineers work 2x faster than Workers and Proletarians.
** Deer and Wild Boar randomly migrate as extra food opportunities until 2000BC.
*** After Refining technology is discovered, Oil Wells on Oil add +2 shields instead of +1 shield.
† Desert River: Irrigating desert rivers gives a forced extra +1 food bonus. Irrigating a city tile also gives a forced extra +1 food bonus. (See Desert Food Output.)
‡ Oasis is a water source for irrigation. 
===Terrain Modification Flowchart===
Note: Formerly, fractional work was impossible; so Terrain Charts previously rounded worker-turns up to the nearest whole number. Starting in MP2-Caravel, Tribesmen work at a rate of ½ worker-turn, and some Wonders and Governments increase work-rates by a fractional percentage. Therefore, exact fractional worker-turns must now be shown. In typical cases without fractional work-rates, simply round up. For example, 2½ worker-turns will take 3 worker-turns to complete.
===Climate Change===
In the default game settings, Global Warming and Nuclear Winter can occur. Too much pollution causes the first, while too much nuclear fallout causes the latter. These events will transform the terrain for percentage of the planet proportional to the accumulated amount of pollution or fallout. The chart below shows what happens to terrain when climate change happens.
Warmer <<< 	>>> Cooler
Jungle 	Forest
Plains 	Tundra
Grassland 	Tundra
Swamp 	Grassland
Desert 	Plains
Tundra 	Arctic
Ocean 	Swamp
Deep ocean	Ocean
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