World-map Text Configuration Files

The Fallout and Fallout 2 world map is not defined by one file. The editable source data is split across three text configuration files:

FileRole
data\maps.txtDefines the map index namespace, MAP filenames, map flags, music, ambient SFX, and random encounter start points.
data\city.txtDefines world-map areas, town-map art, city marker positions, city visibility defaults, and town-map entrances.
data\worldmap.txtDefines terrain types, encounter frequencies, world-map tiles, subtiles, random encounter maps, encounter tables, encounter groups, and encounter conditions.

worldmap.dat is the saved or cached runtime state derived from these definitions. To edit the world map itself, edit these text files and their referenced MAP, FRM, MSK, PRO, script, sound, and message assets first.

Loading order

Fallout 2 CE loads the world-map configuration in this order:

  1. Load text\<language>\game\worldmap.msg for world-map UI and encounter text.
  2. Read data\maps.txt while initializing map lookup data.
  3. Read data\city.txt while initializing world-map areas.
  4. Read data\worldmap.txt while initializing terrain, world-map tiles, and encounter tables.
  5. Initialize runtime state and save/load worldmap.dat state as needed.

The order matters. city.txt entrances resolve map names through maps.txt, and worldmap.txt encounter tables also resolve map names through maps.txt. A tool should load maps.txt before validating either of the other two files.

Engine capacities

The text files do not always state the practical runtime limits. The current CE structures use these capacities:

DataCapacityNotes
Ambient SFX entries per map7Raised from the original-looking 6 to support larger mod data.
Random start points per map15Used mostly by random encounter maps.
Entrances per area10Extra entrance_N keys are not stored.
Random maps per terrain20Fallback map pool for terrain-based random encounters.
Maps per encounter table6Used before the terrain fallback map pool.
Encounter table entries40 parsed entriesThe structure has an extra slot, but the parser stops at 40 normal entries.
Enc: subentries per table entry6Each subentry references one encounter group or player.
Entries per encounter group10type_NN entries beyond the structure limit are unsafe for CE-style parsers.
Items per encounter group entry10Each item: token consumes one slot.
Conditions per encounter/table entry3Joined by up to two and/or qualifiers.

Shared syntax

The three files use the engine's INI-like configuration parser.

RuleBehavior
SectionsSection headers use square brackets, such as [Map 000] or [Encounter Table 0].
Key/value pairsEntries use key=value. Whitespace around the key and value is trimmed.
CommentsA semicolon starts a comment. Everything after the first ; on a line is discarded before parsing.
No quotingThere is no quote or escape syntax in the config parser. Semicolons cannot be kept in values.
CaseSection and key lookup is case-insensitive. Many world-map value parsers lowercase their input before matching tokens.
DuplicatesDuplicate section/key pairs replace earlier values while loading; the last parsed value wins.
IntegersInteger parsing accepts leading numeric text and ignores trailing characters. This is why values such as Frequent=38% parse as 38.
Line lengthFallout 2 CE uses a 256-byte config line buffer. The original worldmap.txt comments mention a smaller Watcom-era path limit, so very long lines should still be avoided for original-tool compatibility.

Most list-like values are comma-separated. The shared string parsers skip leading spaces before each comma-delimited item and match tokens case-insensitively. They also mutate and lowercase the loaded value buffer, so a format-preserving editor should keep its own copy of the original text if it wants to preserve case and spacing.

Numbered sections

Several parts of the world-map config are read as contiguous numbered sequences. Gaps are not skipped; the loader stops at the first missing required key.

SequenceSection/key patternStop condition
Maps[Map 000], [Map 001], ... with required lookup_name.First missing lookup_name.
Areas[Area 00], [Area 01], ... with required townmap_art_idx.First missing townmap_art_idx, then CE checks the final count against its compiled city count.
Encounter tables[Encounter Table 0], [Encounter Table 1], ... with required lookup_name.First missing lookup_name.
World-map tiles[Tile 0], [Tile 1], ... with required art_idx.First missing art_idx.
Area entrancesentrance_0, entrance_1, ...First missing entrance key, or the engine capacity of 10 entrances.
Random mapsmap_00, map_01, ... inside [Random Maps: terrain].First missing map key, or the terrain map capacity.
Encounter entriesenc_00, enc_01, ... inside an encounter table.First missing encounter key, or the CE limit of 40 table entries.
Encounter group entriestype_00, type_01, ... inside [Encounter: name].First missing type key. CE's runtime structure has room for 10 entries.

data\maps.txt

maps.txt defines map indexes. MAP headers, world-map entrances, scripts, encounter tables, map name lookups, and save behavior all depend on this ordering. Once saves or scripts exist, changing map order is a compatibility break.

[Map 000]
lookup_name=Desert Encounter 1
map_name=desert1
music=07desert
ambient_sfx=gustwind:20, gustwin1:20
saved=No
dead_bodies_age=No
can_rest_here=No, No, No
random_start_point_0=elev:0, tile_num:20195

Map section keys

KeyRequiredDescription
lookup_nameYesSymbolic map name. This is the name used by city.txt, worldmap.txt, and engine helper functions.
map_nameYesBase MAP filename. CE lowercases this value and appends .MAP when resolving a map index to a filename.
musicNoBackground music base name, normally without the .ACM extension. If absent or empty, CE simply does not start map music from this field.
ambient_sfxNoComma-separated name:chance list for ambient SFX names, normally without file extensions. CE's current capacity is 7 entries per map.
savedNoYes or No. Controls whether the map is saveable and whether entering it can mark the containing world-map area visited. Default flag state is on.
dead_bodies_ageNoYes or No. Controls dead-body aging. Default flag state is on.
can_rest_hereNoThree Yes/No values, one for elevation 0, 1, and 2. Default flag state is on for all elevations.
pipboy_activeNoYes or No. CE parses the flag, but its current wmMapPipboyActive helper checks the vault-suit movie state instead.
automapNoOptional sfall/CE automap display flag.
random_start_point_NNoRandom encounter start points, each with elev: and tile_num:. CE's current capacity is 15 start points per map.

Classic docs also mention a state key. It is not read by the CE world-map map loader shown in worldmap.cc, so treat it as historical or tool-facing data unless the target engine documents otherwise.

Map defaults and flags

CE initializes each map with flags 0x3F, meaning saved, dead_bodies_age, pipboy_active, and all three can_rest_here elevation flags start enabled. Optional keys override those bits only when present. If a random encounter map should not be saved or rested in, set those keys explicitly.

FlagMeaning
0x01Saved map state is preserved.
0x02Dead bodies age.
0x04Pip-Boy active flag, parsed but not currently used by CE's public helper.
0x08Can rest on elevation 0.
0x10Can rest on elevation 1.
0x20Can rest on elevation 2.

Random start points

random_start_point_N entries are used when placing encounter groups with non-surrounding formations. CE reads elev: and tile_num:; the start-point rotation field exists in memory but defaults to -1 and is not parsed from maps.txt by the current loader.

random_start_point_0=elev:0, tile_num:20195
random_start_point_1=elev:0, tile_num:20305

Tile numbers here are normal MAP hex tile numbers. See MAP File Format for tile numbering.

data\city.txt

city.txt defines the areas shown on the world map and town map. The section number is the area index used by scripts, save state, and map.msg city-name lookups.

[Area 00]
townmap_art_idx=-1
area_name=Arroyo
world_pos=473, 313
start_state=on
lock_state=off
size=medium
entrance_0=on, 258, 168, Arroyo Village, 0, 20195, 0

Area section keys

KeyRequiredDescription
townmap_art_idxYesInterface art index for the town-map image. -1 means no town-map image. The value is converted to an interface FID.
townmap_label_art_idxNoInterface art index for the town-map label. -1 means no label.
area_nameYesInternal area name stored in the city structure. Display names come from map.msg, not from this value.
world_posYesTwo integers: X and Y world-map marker position in pixels.
start_stateYesoff or on. Initial world-map visibility state.
lock_stateNooff or on. Locked areas resist normal visibility changes unless a script forces the change.
sizeYessmall, medium, or large. Selects the world-map marker size/hit shape.
entrance_NNoTown-map entrance definition. Up to 10 are stored by CE.

For Fallout 2 CE, the loaded area count is checked against the compiled Fallout 2 city enum count of 76. Mods that change the number of areas may require engine support, not only text-file edits.

Entrance syntax

entrance_N=state, x, y, map_lookup_name, elevation, tile, rotation
FieldDescription
stateoff or on. Hidden entrances are not available from the town map.
x, yTown-map button/hotspot position.
map_lookup_nameName matched against lookup_name in maps.txt.
elevationDestination elevation. -1 acts as a wildcard when matching an entrance by map/elevation.
tileDestination MAP tile number.
rotationDestination critter rotation, usually 0 through 5.

The first valid entrance can be auto-revealed when entering a city that has no revealed entrance yet. Scripts and map visits can also reveal entrances by map and elevation.

City names

World-map city names are looked up from text\<language>\game\map.msg using message id 1500 + area_index. Map elevation names use map_index * 3 + elevation + 200. Town-map entrance labels are different: CE looks them up from worldmap.msg using message id 200 + 10 * area_index + entrance_index. See MSG File Format.

data\worldmap.txt

worldmap.txt defines the tile grid, terrain, encounter frequencies, and random encounter content. It is the densest of the three files and has the most historical comments that do not map directly to parsed CE behavior.

[data]

[data]
Forced=100%
Frequent=38%
Common=22%
Uncommon=12%
Rare=4%
None=0%
terrain_types=Desert:1, Mountain:2, City:1, Ocean:1
KeyDescription
none, rare, uncommon, common, frequent, forcedEncounter frequency values. Percent signs are tolerated because integer parsing stops after the leading number.
terrain_typesComma-separated name:difficulty list. The loader lowercases the names and stores the difficulty integer.

The source reads frequency keys in the fixed order none, rare, uncommon, common, frequent, forced, stopping that loop at the first missing key. Keep all six for clarity. terrain_short_names appears in some original comments/transcripts, but it is not read by the CE loader.

Terrain difficulty

The terrain difficulty value affects travel speed. During world-map walking, the current subtile's terrain difficulty is clamped to at least 1 and used to decide how often the party advances a pixel. Larger values slow travel. The Pathfinder perk reduces the game-time increment, not the text value itself.

[Random Maps: terrain]

[Random Maps: desert]
map_00=Desert Encounter 1
map_01=Desert Encounter 2

The section name uses the lowercased terrain name as stored from terrain_types. Each map_NN value is matched against maps.txt lookup_name. If an encounter table entry and table do not specify their own map list, the engine selects from the current terrain's random map list.

CE stores 20 map slots per terrain. Validators should reject entries beyond map_19 and should warn when a terrain used by subtiles has no random maps, because fallback encounter map selection can then fail.

[Tile Data]

[Tile Data]
num_horizontal_tiles=4

num_horizontal_tiles defines the width of the world-map tile grid. The height is derived from the number of loaded [Tile N] sections divided by this width. Each whole tile is 350 x 300 pixels and contains a 7 x 6 grid of 50 x 50 subtiles.

[Tile N]

[Tile 0]
art_idx=339
encounter_difficulty=0
walk_mask_name=wrldmp00
0_0=Ocean,Fill_W,None,None,None,Fish_O
0_1=Ocean,Fill_W,None,None,None,Fish_O
KeyRequiredDescription
art_idxYesInterface art list index for the visible world-map FRM tile.
encounter_difficultyNoModifier added to the Outdoorsman detection check for random encounters on this tile.
walk_mask_nameNoBase name of a data\*.msk walk mask. See MSK File Format.
row_columnYesSubtile definition. Every key 0_0 through 6_5 is required.

Tile sections are read from [Tile 0] upward until art_idx is missing. A missing subtile key inside a loaded tile is fatal.

Subtile syntax

row_column=terrain, fill, morning_frequency, afternoon_frequency, night_frequency, encounter_table
FieldDescription
terrainTerrain name from terrain_types.
fillFog fill token: no_fill, fill_n, fill_s, fill_e, fill_w, fill_nw, fill_ne, fill_sw, or fill_se.
morning_frequencyOne of the six frequency names from [data].
afternoon_frequencyOne of the six frequency names from [data].
night_frequencyOne of the six frequency names from [data].
encounter_tablelookup_name from an [Encounter Table N] section.

The coordinate in the key is x_y: X/subtile column 0..6, then Y/subtile row 0..5. CE's loop creates keys in that order: 0_0, 1_0, ... 6_0, then 0_1, and so on.

Encounter tables

[Encounter Table 52]
lookup_name=SRNRRN_M
maps=Mountain Encounter 1, Mountain Encounter 2
enc_00=Chance:8%,Enc:(4-7) KLA_Trappers
enc_01=Chance:2%,Counter:1,Special,Map:Special Toxic Encounter,Enc:Special1, If(Player(Level) > 5)
Key/tokenDescription
lookup_nameName referenced by tile subtiles.
mapsOptional list of up to 6 map lookup names. Used before terrain random maps when an entry does not name a specific map.
enc_NNSequential encounter table entries. CE accepts up to 40 entries per table.
Chance:NRelative entry weight. The values do not need to sum to 100.
Counter:NLimited-use counter. -1 is the default unlimited state; 0 disables the entry; positive values decrement when selected.
SpecialMarks the entry as a special encounter. Special entries can reveal/move the related area marker.
Map:nameSpecific encounter map lookup name. If absent, the table map list or terrain map list is used.
Scenery:nameOptional scenery density token: none, light, normal, or heavy. Default is normal.
Enc:...One or more encounter group references, described below.
If(...)Optional condition expression.

When selecting a random encounter, CE filters entries whose conditions fail or whose counter is 0. It sums the remaining Chance values, adjusts the roll with Luck, Explorer, Ranger, Scout, and game difficulty, then selects a weighted entry. If the selected entry has a positive counter, the counter is decremented and later saved in worldmap.dat.

Enc: subentries

Enc:(4-7) KLA_Trappers
Enc:(3-6) KLA_Trappers AND (4-5) KLAD_Caravan FIGHTING
Enc:player

An Enc: clause contains up to six subentries in CE's runtime structure. Each subentry can start with a count range, then an encounter group name, then an optional situation token.

PartDescription
(min-max)Optional count range. Defaults to 1-1.
Group nameName of an [Encounter: name] section, loaded on demand. The special name player is stored as -1.
Situationnothing, ambush, fighting, or and.

Classic data often writes phrases such as AMBUSH Player. The CE parser stores the situation token and does not store the trailing target word from that phrase.

Encounter groups

[Encounter: KLA_Trappers]
type_00=pid:16777418, item:7(wielded), item:(0-10)41, script:484
type_01=ratio:60%, pid:16777419, item:7(wielded)
team_num=17
position=wedge, spacing:2

Encounter groups describe what objects or critters are spawned when an encounter table subentry references the group.

Key/tokenDescription
type_NNSequential group entries. CE's runtime structure has room for 10 entries.
ratio:NSpawn this entry as a percentage of the requested group count. Without ratio, the entry spawns a single object.
dead,Marks a critter entry as dead at encounter setup.
pid:NPID to create. 0 is normalized to -1.
distance:NPer-entry placement distance override. For surrounding formations, 0 means use Perception plus a small random offset.
tilenum:NFixed MAP tile placement override.
item:NItem PID to add to the spawned object.
item:(min-max)NItem PID with random quantity.
(wielded), {wielded}, (worn), {worn}Marks the item as equipped. CE currently calls the wield path for equipped items.
script:NScript index override. CE passes N - 1 to the script instance creation helper.
if(...)Optional entry condition. enctr(num_critters) conditions can use the current requested group count here.
team_numTeam number applied to critter PID entries in the group.
positionFormation token, with optional spacing: and distance:.

CE reads team_num without checking whether the key was present before applying it to critter entries. Vanilla data generally supplies it where needed; authoring tools should warn when a group with critter PIDs lacks team_num.

Formations

Valid formation tokens are surrounding, straight_line, double_line, wedge, cone, and huddle. The default formation is surrounding, default spacing is 1, and the group-level distance: field is parsed but not used by CE's placement code. Per-entry distance: is used for surrounding placement.

For non-surrounding formations, CE uses a random start point from the current MAP when one exists; otherwise it centers formation placement on the player. The engine rejects placement tiles that are blocked or unreachable by pathfinding and tries alternate tiles before giving up.

Encounter conditions

Encounter table entries and encounter group entries can have up to three conditions joined with and or or.

ConditionRuntime value
if(rand(N))Random roll from 0 to 100; succeeds when the roll is not greater than N.
if(global(N) == value)Global variable N.
if(player(level) > value)Player level.
if(days_played > value)Game time divided by ticks per day.
if(time_of_day < value)Current hour, 0 through 23.
if(enctr(num_critters) < value)Current requested encounter group count; useful inside encounter group entries.

Supported comparison operators are ==, !=, <, and >. The parser has a special placeholder operator _ for random checks. Classic comments mention other operators, but they are not implemented by the CE condition evaluator shown in source.

Condition evaluation is simple and has edge cases. It does not build a full expression tree, supports only three condition entries, and the CE source even notes a possible overflow when all three conditions are specified. Keep expressions short and test unusual or combinations in-game.

Message lookups

The trio is tightly coupled to two message files. The data files store structural names and lookup names, while player-facing text usually comes from MSG resources.

Message fileID patternUse
text\<language>\game\map.msg1500 + area_indexWorld-map city/location names.
text\<language>\game\map.msgmap_index * 3 + elevation + 200Map elevation names used by automap/save UI.
text\<language>\game\worldmap.msg200 + 10 * area_index + entrance_indexTown-map entrance labels.
text\<language>\game\worldmap.msg2998Display-monitor prefix when a random encounter is detected.
text\<language>\game\worldmap.msg2999Random encounter prompt title.
text\<language>\game\worldmap.msg3000 + 50 * encounter_table_index + encounter_entry_indexRandom encounter prompt/body text.

The original city.txt comments say that city names are kept in the world-map message file. In CE source, area names for the visible tabs/markers are read from map.msg; worldmap.msg supplies town-map entrance labels and random encounter text.

Runtime flow

  1. The party's world pixel position selects a world-map tile and subtile.
  2. The subtile selects terrain, encounter frequency by time of day, and encounter table.
  3. The terrain affects travel speed and supplies fallback random maps.
  4. The MSK mask, if present, blocks individual world-map pixels.
  5. The encounter frequency is adjusted by game difficulty and car travel, then random encounters are rolled.
  6. The encounter table filters entries by counters and conditions, then selects a weighted entry.
  7. The selected entry chooses a MAP from Map:, table maps, or terrain random maps.
  8. Encounter groups spawn critters/items and attach scripts/items according to their [Encounter: name] definitions.
  9. Map and city names shown to the player are resolved through map.msg, while encounter prompt text is resolved through worldmap.msg.

Validation checklist

Editing notes

Source references