Terrain

Terrain refers to the different types of tiles found on the map (a.k.a. "the square"). Each map is randomly generated and unique, containing different types of terrain in varying proportions and arrangements.

The three primary terrain types are mountain, forest, and field. Terrain type impacts which resources can be spawned and which buildings can be built. In addition, mountains and forests hinder movement: units cannot move through them, excepting forests with Roads.

Each tribe has a unique set of spawn rates for terrain and resources on land. During the initial map generation, the land is distributed roughly equally between all tribes in the game. The look of different terrain types and resources will by tribe. These varying designs are purely cosmetic and do not impact gameplay. Terrain generation and starting technology are the only differences between regular tribes.

However, Polaris does not have its own set of spawn rates, nor is it accounted for in the initial land allocation. Instead, the map spawns with the terrain of the other tribes, then Polaris freezes the tiles in its territory. (The opposite occurs when a different tribe captures a Polaris city: the terrain of that city's territory is converted to that of the capturing tribe.) If all of the players on a map are playing Polaris, then Imperius terrain, which has unchanged spawn rates, is used.

Terrain Spawn Rates

Standard Spawn Rates

The standard spawn rate for resources are listed in the table below. "Inner city" refers to tile next to a city or village, while "outer city" refers to other land tiles not next to a city.

The standard spawn rate for fish is 50% among shallow water tiles. The spawn rate for whales is 40% among ocean tiles; this rate does not vary by tribe, unlike those of other resources.

All resources (not including empty forests) spawn only within two tiles of cities or villages. This fact can be used to locate villages and enemy cities.

Tribe Spawn Rate Modifiers

• Xin-xi: ++mountain +metal
• Imperius: unchanged
• Bardur: ++game +fruit --crop
• Oumaji: --forest (--water¹)
• Kickoo: -mountain +fish ++water²  
• Hoodrick: -mountain +forest  
• Luxidoor: -game ++fruit 
• Vengir: ++metal --game --fruit +crop --fish  
• Zebasi: -mountain  -forest -fruit
• Ai-Mo: +mountain --crop
• Quetzali: ++fruit --crop
• Yădakk: -mountain -forest +fruit (-water¹)
• Aquarion: -forest +water²
• ∑∫ỹriȱŋ: -mountain +crop 
• Polaris: “alien” - does not have its own set of terrain spawn rates³

¹Reductions to the amount of water are found in the source code but are not actually translated into the world generation and do not actually impact the water rates. 

²Kickoo and Aquarion have 40% and 30%, respectively, of their tiles replaced with water.

³Games where all players are playing Polaris take place on Imperius land, which has the standard spawn rates for all resources.

Terrain Types

Image	Terrain Name	Resources	Information	Buildings
	Cloud	N/A	Any tile that is unexplored will be covered with a cloud. These will disappear when they come into the line of sight of your unit. Clouds also block your units from moving further until the cloud tile is explored. Clouds that disappear are only visible to the player who explores them so you can't see what AI or other players explored.	N/A
	Field	fruit, crop	The default tile. Most normal buildings require this tile. This tile does not block movement. Ruins can spawn on this tile, although resources beneath it will not be revealed until the Ruin is cleared. You can use Grow Forest on a field tile once Spiritualism is researched to convert it into a Forest tile, although this will remove all resources. You may harvest fruit present on the tile for 2 stars yielding 1 population once Organization has been researched. This will turn it into an empty field. Crop will not be revealed until Organization or Farming has been researched. If crop is present on the tile, you may build a Farm on the tile for 5 stars yielding 2 population once Farming has been researched.	Monuments, Farm (requires crop), Sawmill, Windmill, Temple, Customs House, Forge, Sanctuary, Road, Ice Bank
	Forest	wild animal	This tile blocks movement. Land units may never move through this tile without stopping unless Roads are built. Ruins can spawn on this tile, although resources beneath it will not be revealed until the Ruin is cleared. You may hunt wild animals present on this tile for 2 stars yielding 1 population once Hunting has been researched. This will turn it into an empty Forest tile. You can use Clear Forest on a forest tile once Forestry has been researched to convert it into a Field tile and get 2 stars, although this will remove all resources. You can use Burn Forest on a field tile once Chivalry is researched to convert it into a Field tile with crop, although this will remove all resources. If playing as Elyrion, you may Enchant wild animals for 2 stars once Forest Magic is researched. This will turn it into an empty Forest tile and create a Polytaur. Forest provides a 50% defence bonus after Archery has been researched.	Road, Lumber Hut, Sanctuary, Forest Temple
	Mountain	metal	This tile blocks movement. Land units may never move through this tile without stopping. Ruins can spawn on this tile, although resources beneath it will not be revealed until the Ruin is cleared. If metal is present on the tile, you may build a Mine for 5 stars yielding 2 population once Mining has been researched. You must research Climbing before you can move into Mountain tiles. Mountains provide a 50% defence bonus after Meditation has been researched. Moving to a mountain tile allows you to clear clouds 2 tiles away instead of the usual 1.	Mine (requires metal), Mountain Temple, Sanctuary
	Water	fish	Normally Ruins cannot spawn on this tile. You may harvest fish present on the tile for 2 stars yielding 1 population once Fishing has been researched. This will turn it into an empty water tile.	Port, Monuments, Water Temple
	Ocean	whale	Ruins can spawn on this tile, although resources beneath it will not be revealed until the Ruin is cleared. You may harvest whales present on the tile yielding 10 stars once Whaling has been researched. This will turn it into an empty ocean tile. If playing as Elyrion, you may Enchant whales for 5 stars once Water Magic has been researched. This will turn it into an empty Ocean tile and create a Navalon. You must research Navigation (or Free Diving as Aquarion) before you can move into Ocean tiles. Ocean provides a 50% defence bonus after Aquatism has been researched.	Water Temple
	Ice	fish, whale	This is a unique tile, because it is created when water tiles are frozen and thus retains its resources or ruins. This tile does not block movement, but provides double movement to units with the skate skill, and +1 movement to land units if Polarism is unlocked. Units may use Break Ice when adjacent to this tile, reverting all ice tiles within a 3x3 area centered on the caster to water/ocean.	Monuments, Ice Temple, Outpost

Forced Spawning

Bardur, Imperius, Kickoo, Zebasi, and ∑∫ỹriȱŋ are guaranteed to have at least two of the resources they can immediately use in their capital, with resources being force-spawned if the initial world generation does not provide enough.

Fish in ocean and Whales and Ruins in shallow water may occasionally spawn due to a bug caused by forced spawning, where a water tile is replaced by a resource tile, changing the "depth" of its surrounding tiles. Also, if forced spawning affects what was originally a mountain tile, it may continue to provide the increased sight radius despite no longer being a mountain due to another bug.