TerrainCodesWML

Note: the old (1.2) terrain system is no longer documented here. If you have 1.2 maps you will need to convert them using wmllint.

Terrain strings

The following rules hold for terrain strings. Note most of these rules are not validated since it would slow down Wesnoth; not following these rules might break Wesnoth.

terrain strings are composed from one or two terrain codes of 2 to 4 characters (bytes) each, separated by ^.
terrain codes start with a capital letter and the following letters are lower case
terrain strings can only contain letters, the symbols /|\ which are meant for directional items like bridges and the symbol ^
the underscore is used as a leader for internal terrain codes
the star '*' can be used for wildcards in some places where a terrain code is required for matching
the symbol ^ indicates that a terrain is created with layers, for example Gs^Fp means Semi-dry Grass(Gs) with a Forest(Fp) overlay.

Starting positions are defined by a number followed by 1 space and then the terrain string.

The letters Y,y,Z,z are reserved for UMC and mainline campaigns, so any string containing any of these letters is a custom terrain. Other undefined terrain strings are reserved for future expansion within Wesnoth.

Terrain Table

The list of terrains can be found at TerrainCodeTableWML. Since most overlays can be combined with most bases the list is not complete.

Adding terrains

When adding terrains make sure the following files are also checked:

data/multiplayer/factions/* contains favorite positions for the different factions, this is only used for the random map generator at the moment so it is not very important.

data/core/macros/abilities.cfg contains the definition of submerge and ambush so depending on the change these need to be updated.

Decoding the Terrain Codes

The initial letters of each terrain code have a standard meaning, though some are not obvious.

A = “Arctic” i.e. frozen
B = “Bridge”
C = “Castle”
D = “Desert”
E = "Embellishment"
F = “Forest”
G = “Grass” i.e. flat
H = “Hills”
I = "Interior" (possible future use)
J = testing
K = “Keep”
L
M = “Mountains”
N
O
P = “Portal” i.e. doors, gates
Q = "Un-walkable", (Version 1.17.7 and later only) also used for elevation overlays
R = “Road”, also used for “Rails”
S = “Swamp”
T = (Version 1.15.2 and later only) “Toadstool” i.e. fungus
U = “Underground”
V = “Village”
W = “Water”
X = "Impassable"
Y = Reserved for UMC
Z = Reserved for UMC
_ = "special system stuff"

Additional letters do not always follow the same meaning, but are as consistent as possible.

\, |, / = for indicating the direction of bridges
a =
b =
c = "city"
d = "dry or desert, deciduous"
e = "encampment"
f = "flowers, fall"
g
h = "human"
i = "ice"
j
k
l = "lava"
m = "mixed"
n
o = "orc"
p = "pine"
q
r
s = "simple"
t = "archetype", a hidden terrain used only as a base for other terrains
u = "underground"
v = "elvish"
w
x = "chasm"
y = Reserved for UMC
z = Reserved for UMC

Terrain codes in map data

This is not the Matrix. You normally don't need to look at encoded maps. However, it can be beneficial and useful for more advanced users to understand the usage of terrain strings in raw map file.

The encoding for maps has a specific format in Wesnoth:

A map starts with a header with the following keys
- usage, this should be 'map' for a map and 'mask' for an overlay mask
- border_size, the size of the border, should be 1 for map and 0 for mask. When the border_size is 1 the map border is part of the map data, this means the user can define the border instead of the game taking a guess.
- (Version 1.13.12 and later only) These keys are now deprecated and will be ignored if present. The blank line mentioned below is not required if these keys are absent.
Between the header and the data should be 1 empty line
A map data file consists of any number of lines, each with the same number of terrain codes.
Each string may be padded with spaces or tabs and must be separated with a comma, except for the last string on a line this one may not have a comma.
When the file is interpreted, each terrain code will be replaced by the terrain it refers to.
Empty lines are allowed before, after and between lines of characters, between lines is not advised.
Terrains may be prefixed with a number followed by one space, these indicate the starting position for side n.
- For Wesnoth 1.12.6, n = 1, 2, 3, ... 9, and the multiplayer server will refuse maps with more than 9 sides.
- For Wesnoth 1.14, more than 9 sides can work, discussion https://r.wesnoth.org/t48129 and https://r.wesnoth.org/t48082
(Version 1.13.12 and later only) In addition to side numbers, terrains may be prefixed by any number of strings (which should consist of alphanumeric characters only, including underscores). All names and side numbers must be delimited by spaces and are separated from the actual terrain code by an additional space.
- This is broken according to https://r.wesnoth.org/p627595

Since text file tiles are squares while game tiles are hexes, some tiles must be shifted. Tiles in even-numbered columns are shifted down 1/2 of a tile. For example, to have a road of connected dirt ('Re') tiles, the map data would look like this:

usage=map
border_size=1

Re, Re, Gg, Gg, Gg, Gg, Gg, Gg
Gg, Gg, Re, Re, Gg, Gg, Gg, Gg
Gg, Gg, Gg, Gg, Re, Re, Gg, Gg
Gg, Gg, Gg, Gg, Gg, Gg, Re, Re