Map exchange string format

This is a technical description of the map exchange string format, used to share map generating configurations with other users.

Factorio line wraps the entire map exchange string after 55 characters during export, but ignores all whitespace during import. The outer layer of the map exchange string format includes three angle brackets on either side: ">>>" and "<<<", which must be present for Factorio to accept the string. Between those two tokens is the map exchange data, encoded using base 64 as defined by RFC 4648 (or 3548, 2535, 2045, 1421, et al).

This document will use the terms "int" to refer to 4 byte numbers and "short" to refer to 2 byte numbers. All numerical values are stored in unsigned little-endian format. "boolean" is a single byte that represents true if equal to 1, otherwise it is equal to false. "string"s are Pascal-style int length prefixed strings. The format described below is valid at least for Factorio 0.14.x, older versions may use a different encoding scheme.

Factorio 0.14 and Beyond

This is the base map exchange string format for all Factorio versions 0.14.x and greater.

short[4]	The version string of Factorio that generated this string, used to determine encoding format.
byte	Water frequency.
byte	Water size.
ore_def[int]	An array of ore definitions. The array length is stored as an integer prefix. Factorio doesn’t care what order these are in, but it always alphabetizes during export. Vanilla has seven resources: coal, copper-ore, crude-oil, enemy-base, iron-ore, stone, and uranium-ore. Unknown ores are ignored and missing ores are set to their defaults.
int	Map seed.
int	Map width.
int	Map height.
byte	Starting area size.
boolean	Peaceful mode. Enabled if set to 1, disabled otherwise.
byte[*]	0.15.x map settings, if version >= 0.15. This chunk consists of the remainder of the data (minus the checksum)
int	CRC32 checksum of all preceding data, as defined by ANSI X3.66 / FIPS 71 / ITU-T V.42 (the same one used by zlib, ethernet, etc.)

0.15 Map Settings

All of the following data fields (until noted at the end) have a special encapsulation format. Preceding each value is a single byte that states whether or not the value is present. If the byte is equal to zero, then the field value is not present. Otherwise, then the field's value follows. In this section, the data type "double" refers to the 64-bit floating point format described by IEEE 754.

In the LUA structure, this information is stored in the "map_settings" table, which is created by the "map-settings" prototype. Each section in the table below represents a nested sub-table in "map-settings", where the LUA key listed is the key of the table, and all subsequent fields are part of the sub-table. See data/base/prototypes/map-settings.lua for a description of all attributes.

Type	LUA key	Description
*	pollution	Pollution
boolean	enabled	Pollution enabled.
double	diffusion_ratio	Diffusion ratio.
double	min_to_diffuse	???
double	ageing	Dissipation rate.
double	expected_max_per_chunk	???
double	min_to_show_per_chunk	???
double	min_pollution_to_damage_trees	Minimum to damage trees.
double	pollution_with_max_forest_damage	???
double	pollution_per_tree_damage	???
double	pollution_restored_per_tree_damage	Absorbed per damaged tree.
double	max_pollution_to_restore_trees	???
*	steering.default	Steering (Default)
double	???	???
double	???	???
double	separation_force	???
boolean	force_unit_fuzzy_goto_behavior	???
*	steering.moving	Steering (Moving)
double	???	???
double	???	???
double	separation_force	???
boolean	force_unit_fuzzy_goto_behavior	???
*	enemy_evolution	Evolution
boolean	enabled	Evolution enabled.
double	time_factor	Time factor.
double	destroy_factor	Destroy factor.
double	pollution_factor	Pollution factor.
*	enemy_expansion	Enemy Expansion
boolean	enabled	Enemy expansion enabled.
int	max_expansion_distance	Maximum expansion distance.
int	friendly_base_influence_radius	???
int	enemy_building_influence_radius	???
double	building_coefficient	???
double	other_base_coefficient	???
double	neighbouring_chunk_coefficient	???
double	neighbouring_base_chunk_coefficient	???
double	max_colliding_tiles_coefficient	???
int	settler_group_min_size	Minimum group size.
int	settler_group_max_size	Maximum group size.
int	min_expansion_cooldown	Minimum cooldown.
int	max_expansion_cooldown	Maximum cooldown.
*	unit_group	Unit Group
int	min_group_gathering_time	???
int	max_group_gathering_time	???
int	max_wait_time_for_late_members	???
double	max_group_radius	???
double	min_group_radius	???
double	max_member_speedup_when_behind	???
double	max_member_slowdown_when_ahead	???
double	max_group_slowdown_factor	???
double	max_group_member_fallback_factor	???
double	member_disown_distance	???
int	tick_tolerance_when_member_arrives	???
int	max_gathering_unit_groups	???
int	max_unit_group_size	???
*	path_finder	Path Finder
int	fwd2bwd_ratio	???
double	goal_pressure_ratio	???
bool	use_path_cache	???
double	max_steps_worked_per_tick	???
int	short_cache_size	???
int	long_cache_size	???
double	short_cache_min_cacheable_distance	???
int	short_cache_min_algo_steps_to_cache	???
double	long_cache_min_cacheable_distance	???
int	cache_max_connect_to_cache_steps_multiplier	???
double	cache_accept_path_start_distance_ratio	???
double	cache_accept_path_end_distance_ratio	???
double	negative_cache_accept_path_start_distance_ratio	???
double	negative_cache_accept_path_end_distance_ratio	???
double	cache_path_start_distance_rating_multiplier	???
double	cache_path_end_distance_rating_multiplier	???
double	stale_enemy_with_same_destination_collision_penalty	???
double	ignore_moving_enemy_collision_distance	???
double	enemy_with_different_destination_collision_penalty	???
double	general_entity_collision_penalty	???
double	general_entity_subsequent_collision_penalty	???
int	max_clients_to_accept_any_new_request	???
int	max_clients_to_accept_short_new_request	???
int	direct_distance_to_consider_short_request	???
int	short_request_max_steps	???
double	short_request_ratio	???
int	min_steps_to_check_path_find_termination	???
double	start_to_goal_cost_multiplier_to_terminate_path_find	???
Note: The following fields do not use the special encapsulation method.
byte[4]	. (root)	Other
int	max_failed_behavior_count	???
byte[10]	difficulty_settings	Difficulty Settings
byte	recipe_difficulty	Recipe difficulty. 0 for Normal, 1 for Expensive.
byte	technology_difficulty	Technology difficulty. 0 for Normal, 1 for Expensive.
double	technology_price_multiplier	Technology price multiplier.
Type	LUA key	Description

Ore_def Ore Definitions

See the page on world generation for more information on frequency, size, and richness.

string	Ore name.
byte	Ore frequency.
byte	Ore size.
byte	Ore richness.

Magnitudes (Frequencies / Sizes / Richness)

These are the values used for the frequencies, sizes, and richnesses of ores, water, and the starting area size. None is a valid value for all three options. Anything greater than 5 will crash the game!

0	None / None /None
1	Very Low / Small / Poor
2	Low / Small / Poor
3	Normal / Medium / Regular
4	High / Big / Good
5	Very High / Big / Good