Add engine/overworld/wildmons.asm (without data files).

9 files changed, 222 insertions, 159 deletions

diff --git a/data/text/common_1.asm b/data/text/common_1.asm
index fab936d0..169cc9a9 100755
--- a/data/text/common_1.asm
+++ b/data/text/common_1.asm
@@ -993,7 +993,7 @@ _ButNoSpaceText::
 	line "no space left…"
 	done
 
-UnknownText_0x1bd34b::
+_JustSawSomeRareMonText::
 	text "I just saw some"
 	line "rare @"
 	text_ram wStringBuffer1
@@ -1007,7 +1007,7 @@ UnknownText_0x1bd34b::
 	cont "#MON, OK?"
 	prompt
 
-UnknownText_0x1bd39e::
+_SavingRecordText::
 	text "SAVING RECORD…"
 	line "DON'T TURN OFF!"
 	done
diff --git a/data/wild/johto_grass.asm b/data/wild/johto_grass.asm
index f241dd5d..2567e9fc 100644
--- a/data/wild/johto_grass.asm
+++ b/data/wild/johto_grass.asm
@@ -1,6 +1,8 @@
 ; Johto Pokémon in grass
 
-	map SPROUT_TOWER_2F
+JohtoGrassWildMons:
+
+	map_id SPROUT_TOWER_2F
 	db 2 percent, 2 percent, 2 percent ; encounter rates: morn/day/nite
 	; morn
 	db 3, RATTATA
@@ -27,7 +29,7 @@
 	db 5, RATTATA
 	db 5, RATTATA
 
-	map SPROUT_TOWER_3F
+	map_id SPROUT_TOWER_3F
 	db 2 percent, 2 percent, 2 percent ; encounter rates: morn/day/nite
 	; morn
 	db 3, RATTATA
@@ -54,7 +56,7 @@
 	db 5, RATTATA
 	db 5, RATTATA
 
-	map TIN_TOWER_2F
+	map_id TIN_TOWER_2F
 	db 2 percent, 2 percent, 2 percent ; encounter rates: morn/day/nite
 	; morn
 	db 20, RATTATA
@@ -81,7 +83,7 @@
 	db 24, RATTATA
 	db 24, RATTATA
 
-	map TIN_TOWER_3F
+	map_id TIN_TOWER_3F
 	db 2 percent, 2 percent, 2 percent ; encounter rates: morn/day/nite
 	; morn
 	db 20, RATTATA
@@ -108,7 +110,7 @@
 	db 24, RATTATA
 	db 24, RATTATA
 
-	map TIN_TOWER_4F
+	map_id TIN_TOWER_4F
 	db 2 percent, 2 percent, 2 percent ; encounter rates: morn/day/nite
 	; morn
 	db 20, RATTATA
@@ -135,7 +137,7 @@
 	db 24, RATTATA
 	db 24, RATTATA
 
-	map TIN_TOWER_5F
+	map_id TIN_TOWER_5F
 	db 2 percent, 2 percent, 2 percent ; encounter rates: morn/day/nite
 	; morn
 	db 20, RATTATA
@@ -162,7 +164,7 @@
 	db 24, RATTATA
 	db 24, RATTATA
 
-	map TIN_TOWER_6F
+	map_id TIN_TOWER_6F
 	db 2 percent, 2 percent, 2 percent ; encounter rates: morn/day/nite
 	; morn
 	db 20, RATTATA
@@ -189,7 +191,7 @@
 	db 24, RATTATA
 	db 24, RATTATA
 
-	map TIN_TOWER_7F
+	map_id TIN_TOWER_7F
 	db 2 percent, 2 percent, 2 percent ; encounter rates: morn/day/nite
 	; morn
 	db 20, RATTATA
@@ -216,7 +218,7 @@
 	db 24, RATTATA
 	db 24, RATTATA
 
-	map TIN_TOWER_8F
+	map_id TIN_TOWER_8F
 	db 2 percent, 2 percent, 2 percent ; encounter rates: morn/day/nite
 	; morn
 	db 20, RATTATA
@@ -243,7 +245,7 @@
 	db 24, RATTATA
 	db 24, RATTATA
 
-	map TIN_TOWER_9F
+	map_id TIN_TOWER_9F
 	db 2 percent, 2 percent, 2 percent ; encounter rates: morn/day/nite
 	; morn
 	db 20, RATTATA
@@ -270,7 +272,7 @@
 	db 24, RATTATA
 	db 24, RATTATA
 
-	map BURNED_TOWER_1F
+	map_id BURNED_TOWER_1F
 	db 4 percent, 4 percent, 4 percent ; encounter rates: morn/day/nite
 	; morn
 	db 13, RATTATA
@@ -297,7 +299,7 @@
 	db 15, RATICATE
 	db 15, RATICATE
 
-	map BURNED_TOWER_B1F
+	map_id BURNED_TOWER_B1F
 	db 6 percent, 6 percent, 6 percent ; encounter rates: morn/day/nite
 	; morn
 	db 14, RATTATA
@@ -324,7 +326,7 @@
 	db 16, KOFFING
 	db 16, WEEZING
 
-	map NATIONAL_PARK
+	map_id NATIONAL_PARK
 	db 10 percent, 10 percent, 10 percent ; encounter rates: morn/day/nite
 	; morn
 	db 12, NIDORAN_M
@@ -351,7 +353,7 @@
 	db 12, VENONAT
 	db 12, VENONAT
 
-	map RUINS_OF_ALPH_OUTSIDE
+	map_id RUINS_OF_ALPH_OUTSIDE
 	db 4 percent, 4 percent, 4 percent ; encounter rates: morn/day/nite
 	; morn
 	db 20, NATU
@@ -378,7 +380,7 @@
 	db 22, QUAGSIRE
 	db 22, QUAGSIRE
 
-	map RUINS_OF_ALPH_INNER_CHAMBER
+	map_id RUINS_OF_ALPH_INNER_CHAMBER
 	db 6 percent, 6 percent, 6 percent ; encounter rates: morn/day/nite
 	; morn
 	db 5, UNOWN
@@ -405,7 +407,7 @@
 	db 5, UNOWN
 	db 5, UNOWN
 
-	map UNION_CAVE_1F
+	map_id UNION_CAVE_1F
 	db 6 percent, 6 percent, 6 percent ; encounter rates: morn/day/nite
 	; morn
 	db 6, GEODUDE
@@ -432,7 +434,7 @@
 	db 6, ONIX
 	db 6, ONIX
 
-	map UNION_CAVE_B1F
+	map_id UNION_CAVE_B1F
 	db 6 percent, 6 percent, 6 percent ; encounter rates: morn/day/nite
 	; morn
 	db 8, GEODUDE
@@ -459,7 +461,7 @@
 	db 8, RATTATA
 	db 8, RATTATA
 
-	map UNION_CAVE_B2F
+	map_id UNION_CAVE_B2F
 	db 4 percent, 4 percent, 4 percent ; encounter rates: morn/day/nite
 	; morn
 	db 22, ZUBAT
@@ -486,7 +488,7 @@
 	db 23, ONIX
 	db 23, ONIX
 
-	map SLOWPOKE_WELL_B1F
+	map_id SLOWPOKE_WELL_B1F
 	db 2 percent, 2 percent, 2 percent ; encounter rates: morn/day/nite
 	; morn
 	db 5, ZUBAT
@@ -513,7 +515,7 @@
 	db 8, SLOWPOKE
 	db 8, SLOWPOKE
 
-	map SLOWPOKE_WELL_B2F
+	map_id SLOWPOKE_WELL_B2F
 	db 2 percent, 2 percent, 2 percent ; encounter rates: morn/day/nite
 	; morn
 	db 21, ZUBAT
@@ -540,7 +542,7 @@
 	db 23, SLOWPOKE
 	db 23, SLOWPOKE
 
-	map ILEX_FOREST
+	map_id ILEX_FOREST
 	db 4 percent, 4 percent, 4 percent ; encounter rates: morn/day/nite
 	; morn
 	db 5, CATERPIE
@@ -567,7 +569,7 @@
 	db 6, PARAS
 	db 6, PARAS
 
-	map MOUNT_MORTAR_1F_OUTSIDE
+	map_id MOUNT_MORTAR_1F_OUTSIDE
 	db 6 percent, 6 percent, 6 percent ; encounter rates: morn/day/nite
 	; morn
 	db 14, RATTATA
@@ -594,7 +596,7 @@
 	db 16, RATICATE
 	db 16, RATICATE
 
-	map MOUNT_MORTAR_1F_INSIDE
+	map_id MOUNT_MORTAR_1F_INSIDE
 	db 6 percent, 6 percent, 6 percent ; encounter rates: morn/day/nite
 	; morn
 	db 13, GEODUDE
@@ -621,7 +623,7 @@
 	db 15, GOLBAT
 	db 15, GOLBAT
 
-	map MOUNT_MORTAR_2F_INSIDE
+	map_id MOUNT_MORTAR_2F_INSIDE
 	db 6 percent, 6 percent, 6 percent ; encounter rates: morn/day/nite
 	; morn
 	db 31, GRAVELER
@@ -648,7 +650,7 @@
 	db 32, GOLBAT
 	db 32, GOLBAT
 
-	map MOUNT_MORTAR_B1F
+	map_id MOUNT_MORTAR_B1F
 	db 6 percent, 6 percent, 6 percent ; encounter rates: morn/day/nite
 	; morn
 	db 15, ZUBAT
@@ -675,7 +677,7 @@
 	db 18, RATICATE
 	db 18, RATICATE
 
-	map ICE_PATH_1F
+	map_id ICE_PATH_1F
 	db 2 percent, 2 percent, 2 percent ; encounter rates: morn/day/nite
 	; morn
 	db 21, SWINUB
@@ -702,7 +704,7 @@
 	db 22, GOLBAT
 	db 22, GOLBAT
 
-	map ICE_PATH_B1F
+	map_id ICE_PATH_B1F
 	db 2 percent, 2 percent, 2 percent ; encounter rates: morn/day/nite
 	; morn
 	db 22, SWINUB
@@ -729,7 +731,7 @@
 	db 23, GOLBAT
 	db 22, SNEASEL
 
-	map ICE_PATH_B2F_MAHOGANY_SIDE
+	map_id ICE_PATH_B2F_MAHOGANY_SIDE
 	db 2 percent, 2 percent, 2 percent ; encounter rates: morn/day/nite
 	; morn
 	db 23, SWINUB
@@ -756,7 +758,7 @@
 	db 22, SNEASEL
 	db 24, SNEASEL
 
-	map ICE_PATH_B2F_BLACKTHORN_SIDE
+	map_id ICE_PATH_B2F_BLACKTHORN_SIDE
 	db 2 percent, 2 percent, 2 percent ; encounter rates: morn/day/nite
 	; morn
 	db 23, SWINUB
@@ -783,7 +785,7 @@
 	db 22, SNEASEL
 	db 24, SNEASEL
 
-	map ICE_PATH_B3F
+	map_id ICE_PATH_B3F
 	db 2 percent, 2 percent, 2 percent ; encounter rates: morn/day/nite
 	; morn
 	db 24, SWINUB
@@ -810,7 +812,7 @@
 	db 24, SNEASEL
 	db 26, SNEASEL
 
-	map WHIRL_ISLAND_NW
+	map_id WHIRL_ISLAND_NW
 	db 6 percent, 6 percent, 6 percent ; encounter rates: morn/day/nite
 	; morn
 	db 22, KRABBY
@@ -837,7 +839,7 @@
 	db 24, GOLBAT
 	db 24, GOLBAT
 
-	map WHIRL_ISLAND_NE
+	map_id WHIRL_ISLAND_NE
 	db 6 percent, 6 percent, 6 percent ; encounter rates: morn/day/nite
 	; morn
 	db 22, KRABBY
@@ -864,7 +866,7 @@
 	db 24, GOLBAT
 	db 24, GOLBAT
 
-	map WHIRL_ISLAND_SW
+	map_id WHIRL_ISLAND_SW
 	db 6 percent, 6 percent, 6 percent ; encounter rates: morn/day/nite
 	; morn
 	db 22, KRABBY
@@ -891,7 +893,7 @@
 	db 24, GOLBAT
 	db 24, GOLBAT
 
-	map WHIRL_ISLAND_CAVE
+	map_id WHIRL_ISLAND_CAVE
 	db 6 percent, 6 percent, 6 percent ; encounter rates: morn/day/nite
 	; morn
 	db 22, KRABBY
@@ -918,7 +920,7 @@
 	db 24, GOLBAT
 	db 24, GOLBAT
 
-	map WHIRL_ISLAND_SE
+	map_id WHIRL_ISLAND_SE
 	db 6 percent, 6 percent, 6 percent ; encounter rates: morn/day/nite
 	; morn
 	db 22, KRABBY
@@ -945,7 +947,7 @@
 	db 24, GOLBAT
 	db 24, GOLBAT
 
-	map WHIRL_ISLAND_B1F
+	map_id WHIRL_ISLAND_B1F
 	db 6 percent, 6 percent, 6 percent ; encounter rates: morn/day/nite
 	; morn
 	db 23, KRABBY
@@ -972,7 +974,7 @@
 	db 25, GOLBAT
 	db 25, GOLBAT
 
-	map WHIRL_ISLAND_B2F
+	map_id WHIRL_ISLAND_B2F
 	db 6 percent, 6 percent, 6 percent ; encounter rates: morn/day/nite
 	; morn
 	db 24, KRABBY
@@ -999,7 +1001,7 @@
 	db 26, GOLBAT
 	db 26, GOLBAT
 
-	map WHIRL_ISLAND_LUGIA_CHAMBER
+	map_id WHIRL_ISLAND_LUGIA_CHAMBER
 	db 6 percent, 6 percent, 6 percent ; encounter rates: morn/day/nite
 	; morn
 	db 25, KRABBY
@@ -1026,7 +1028,7 @@
 	db 27, GOLBAT
 	db 27, GOLBAT
 
-	map SILVER_CAVE_ROOM_1
+	map_id SILVER_CAVE_ROOM_1
 	db 6 percent, 6 percent, 6 percent ; encounter rates: morn/day/nite
 	; morn
 	db 43, GRAVELER
@@ -1053,7 +1055,7 @@
 	db 46, GOLBAT
 	db 46, GOLBAT
 
-	map SILVER_CAVE_ROOM_2
+	map_id SILVER_CAVE_ROOM_2
 	db 6 percent, 6 percent, 6 percent ; encounter rates: morn/day/nite
 	; morn
 	db 48, GOLBAT
@@ -1080,7 +1082,7 @@
 	db 45, MISDREAVUS
 	db 45, MISDREAVUS
 
-	map SILVER_CAVE_ROOM_3
+	map_id SILVER_CAVE_ROOM_3
 	db 6 percent, 6 percent, 6 percent ; encounter rates: morn/day/nite
 	; morn
 	db 51, GOLBAT
@@ -1107,7 +1109,7 @@
 	db 53, GOLBAT
 	db 53, GOLBAT
 
-	map SILVER_CAVE_ITEM_ROOMS
+	map_id SILVER_CAVE_ITEM_ROOMS
 	db 6 percent, 6 percent, 6 percent ; encounter rates: morn/day/nite
 	; morn
 	db 48, GOLBAT
@@ -1134,7 +1136,7 @@
 	db 50, PARASECT
 	db 52, PARASECT
 
-	map DARK_CAVE_VIOLET_ENTRANCE
+	map_id DARK_CAVE_VIOLET_ENTRANCE
 	db 4 percent, 4 percent, 4 percent ; encounter rates: morn/day/nite
 	; morn
 	db 3, GEODUDE
@@ -1161,7 +1163,7 @@
 	db 4, ZUBAT
 	db 4, DUNSPARCE
 
-	map DARK_CAVE_BLACKTHORN_ENTRANCE
+	map_id DARK_CAVE_BLACKTHORN_ENTRANCE
 	db 4 percent, 4 percent, 4 percent ; encounter rates: morn/day/nite
 	; morn
 	db 23, GEODUDE
@@ -1188,7 +1190,7 @@
 	db 23, GOLBAT
 	db 23, GOLBAT
 
-	map ROUTE_29
+	map_id ROUTE_29
 	db 10 percent, 10 percent, 10 percent ; encounter rates: morn/day/nite
 	; morn
 	db 2, PIDGEY
@@ -1215,7 +1217,7 @@
 	db 3, HOOTHOOT
 	db 3, HOOTHOOT
 
-	map ROUTE_30
+	map_id ROUTE_30
 	db 10 percent, 10 percent, 10 percent ; encounter rates: morn/day/nite
 	; morn
 	db 3, LEDYBA
@@ -1242,7 +1244,7 @@
 	db 4, HOOTHOOT
 	db 4, HOOTHOOT
 
-	map ROUTE_31
+	map_id ROUTE_31
 	db 10 percent, 10 percent, 10 percent ; encounter rates: morn/day/nite
 	; morn
 	db 4, LEDYBA
@@ -1269,7 +1271,7 @@
 	db 5, GASTLY
 	db 5, GASTLY
 
-	map ROUTE_32
+	map_id ROUTE_32
 	db 10 percent, 10 percent, 10 percent ; encounter rates: morn/day/nite
 	; morn
 	db 4, EKANS
@@ -1296,7 +1298,7 @@
 	db 7, GASTLY
 	db 7, GASTLY
 
-	map ROUTE_33
+	map_id ROUTE_33
 	db 10 percent, 10 percent, 10 percent ; encounter rates: morn/day/nite
 	; morn
 	db 6, RATTATA
@@ -1323,7 +1325,7 @@
 	db 7, RATTATA
 	db 7, RATTATA
 
-	map ROUTE_34
+	map_id ROUTE_34
 	db 10 percent, 10 percent, 10 percent ; encounter rates: morn/day/nite
 	; morn
 	db 10, SNUBBULL
@@ -1350,7 +1352,7 @@
 	db 10, DITTO
 	db 10, DITTO
 
-	map ROUTE_35
+	map_id ROUTE_35
 	db 10 percent, 10 percent, 10 percent ; encounter rates: morn/day/nite
 	; morn
 	db 12, SNUBBULL
@@ -1377,7 +1379,7 @@
 	db 10, DITTO
 	db 12, YANMA
 
-	map ROUTE_36
+	map_id ROUTE_36
 	db 10 percent, 10 percent, 10 percent ; encounter rates: morn/day/nite
 	; morn
 	db 4, LEDYBA
@@ -1404,7 +1406,7 @@
 	db 5, GASTLY
 	db 5, GASTLY
 
-	map ROUTE_37
+	map_id ROUTE_37
 	db 10 percent, 10 percent, 10 percent ; encounter rates: morn/day/nite
 	; morn
 	db 13, LEDYBA
@@ -1431,7 +1433,7 @@
 	db 15, ARIADOS
 	db 15, ARIADOS
 
-	map ROUTE_38
+	map_id ROUTE_38
 	db 10 percent, 10 percent, 10 percent ; encounter rates: morn/day/nite
 	; morn
 	db 16, RATTATA
@@ -1458,7 +1460,7 @@
 	db 16, MEOWTH
 	db 16, MEOWTH
 
-	map ROUTE_39
+	map_id ROUTE_39
 	db 2 percent, 2 percent, 2 percent ; encounter rates: morn/day/nite
 	; morn
 	db 16, RATTATA
@@ -1485,7 +1487,7 @@
 	db 18, MEOWTH
 	db 18, MEOWTH
 
-	map ROUTE_42
+	map_id ROUTE_42
 	db 10 percent, 10 percent, 10 percent ; encounter rates: morn/day/nite
 	; morn
 	db 13, EKANS
@@ -1512,7 +1514,7 @@
 	db 16, GOLBAT
 	db 16, GOLBAT
 
-	map ROUTE_43
+	map_id ROUTE_43
 	db 10 percent, 10 percent, 10 percent ; encounter rates: morn/day/nite
 	; morn
 	db 15, SENTRET
@@ -1539,7 +1541,7 @@
 	db 17, VENOMOTH
 	db 17, VENOMOTH
 
-	map ROUTE_44
+	map_id ROUTE_44
 	db 10 percent, 10 percent, 10 percent ; encounter rates: morn/day/nite
 	; morn
 	db 23, TANGELA
@@ -1566,7 +1568,7 @@
 	db 26, POLIWHIRL
 	db 26, POLIWHIRL
 
-	map ROUTE_45
+	map_id ROUTE_45
 	db 10 percent, 10 percent, 10 percent ; encounter rates: morn/day/nite
 	; morn
 	db 23, GEODUDE
@@ -1593,7 +1595,7 @@
 	db 27, GRAVELER
 	db 27, GRAVELER
 
-	map ROUTE_46
+	map_id ROUTE_46
 	db 10 percent, 10 percent, 10 percent ; encounter rates: morn/day/nite
 	; morn
 	db 2, GEODUDE
@@ -1620,7 +1622,7 @@
 	db 2, RATTATA
 	db 2, RATTATA
 
-	map SILVER_CAVE_OUTSIDE
+	map_id SILVER_CAVE_OUTSIDE
 	db 10 percent, 10 percent, 10 percent ; encounter rates: morn/day/nite
 	; morn
 	db 41, TANGELA
diff --git a/data/wild/johto_water.asm b/data/wild/johto_water.asm
index a4d957ef..83e33b2d 100644
--- a/data/wild/johto_water.asm
+++ b/data/wild/johto_water.asm
@@ -1,228 +1,230 @@
 ; Johto Pokémon in water
 
-	map RUINS_OF_ALPH_OUTSIDE
+JohtoWaterWildMons:
+
+	map_id RUINS_OF_ALPH_OUTSIDE
 	db 2 percent ; encounter rate
 	db 15, WOOPER
 	db 20, QUAGSIRE
 	db 15, QUAGSIRE
 
-	map UNION_CAVE_1F
+	map_id UNION_CAVE_1F
 	db 2 percent ; encounter rate
 	db 15, WOOPER
 	db 20, QUAGSIRE
 	db 15, QUAGSIRE
 
-	map UNION_CAVE_B1F
+	map_id UNION_CAVE_B1F
 	db 2 percent ; encounter rate
 	db 15, WOOPER
 	db 20, QUAGSIRE
 	db 15, QUAGSIRE
 
-	map UNION_CAVE_B2F
+	map_id UNION_CAVE_B2F
 	db 4 percent ; encounter rate
 	db 15, TENTACOOL
 	db 20, QUAGSIRE
 	db 20, TENTACRUEL
 
-	map SLOWPOKE_WELL_B1F
+	map_id SLOWPOKE_WELL_B1F
 	db 2 percent ; encounter rate
 	db 15, SLOWPOKE
 	db 20, SLOWPOKE
 	db 10, SLOWPOKE
 
-	map SLOWPOKE_WELL_B2F
+	map_id SLOWPOKE_WELL_B2F
 	db 2 percent ; encounter rate
 	db 15, SLOWPOKE
 	db 20, SLOWPOKE
 	db 20, SLOWBRO
 
-	map ILEX_FOREST
+	map_id ILEX_FOREST
 	db 2 percent ; encounter rate
 	db 15, PSYDUCK
 	db 10, PSYDUCK
 	db 15, GOLDUCK
 
-	map MOUNT_MORTAR_1F_OUTSIDE
+	map_id MOUNT_MORTAR_1F_OUTSIDE
 	db 4 percent ; encounter rate
 	db 15, GOLDEEN
 	db 20, MARILL
 	db 20, SEAKING
 
-	map MOUNT_MORTAR_2F_INSIDE
+	map_id MOUNT_MORTAR_2F_INSIDE
 	db 2 percent ; encounter rate
 	db 20, GOLDEEN
 	db 25, MARILL
 	db 25, SEAKING
 
-	map MOUNT_MORTAR_B1F
+	map_id MOUNT_MORTAR_B1F
 	db 2 percent ; encounter rate
 	db 15, GOLDEEN
 	db 20, MARILL
 	db 20, SEAKING
 
-	map WHIRL_ISLAND_SW
+	map_id WHIRL_ISLAND_SW
 	db 4 percent ; encounter rate
 	db 20, TENTACOOL
 	db 15, HORSEA
 	db 20, TENTACRUEL
 
-	map WHIRL_ISLAND_B2F
+	map_id WHIRL_ISLAND_B2F
 	db 4 percent ; encounter rate
 	db 15, HORSEA
 	db 20, HORSEA
 	db 20, TENTACRUEL
 
-	map WHIRL_ISLAND_LUGIA_CHAMBER
+	map_id WHIRL_ISLAND_LUGIA_CHAMBER
 	db 4 percent ; encounter rate
 	db 20, HORSEA
 	db 20, TENTACRUEL
 	db 20, SEADRA
 
-	map SILVER_CAVE_ROOM_2
+	map_id SILVER_CAVE_ROOM_2
 	db 2 percent ; encounter rate
 	db 35, SEAKING
 	db 35, GOLDUCK
 	db 35, GOLDEEN
 
-	map DARK_CAVE_VIOLET_ENTRANCE
+	map_id DARK_CAVE_VIOLET_ENTRANCE
 	db 2 percent ; encounter rate
 	db 15, MAGIKARP
 	db 10, MAGIKARP
 	db 5, MAGIKARP
 
-	map DARK_CAVE_BLACKTHORN_ENTRANCE
+	map_id DARK_CAVE_BLACKTHORN_ENTRANCE
 	db 2 percent ; encounter rate
 	db 15, MAGIKARP
 	db 10, MAGIKARP
 	db 5, MAGIKARP
 
-	map DRAGONS_DEN_B1F
+	map_id DRAGONS_DEN_B1F
 	db 4 percent ; encounter rate
 	db 15, MAGIKARP
 	db 10, MAGIKARP
 	db 10, DRATINI
 
-	map OLIVINE_PORT
+	map_id OLIVINE_PORT
 	db 2 percent ; encounter rate
 	db 20, TENTACOOL
 	db 15, TENTACOOL
 	db 20, TENTACRUEL
 
-	map ROUTE_30
+	map_id ROUTE_30
 	db 2 percent ; encounter rate
 	db 20, POLIWAG
 	db 15, POLIWAG
 	db 20, POLIWHIRL
 
-	map ROUTE_31
+	map_id ROUTE_31
 	db 2 percent ; encounter rate
 	db 20, POLIWAG
 	db 15, POLIWAG
 	db 20, POLIWHIRL
 
-	map ROUTE_32
+	map_id ROUTE_32
 	db 6 percent ; encounter rate
 	db 15, TENTACOOL
 	db 20, QUAGSIRE
 	db 20, TENTACRUEL
 
-	map ROUTE_34
+	map_id ROUTE_34
 	db 6 percent ; encounter rate
 	db 20, TENTACOOL
 	db 15, TENTACOOL
 	db 20, TENTACRUEL
 
-	map ROUTE_35
+	map_id ROUTE_35
 	db 4 percent ; encounter rate
 	db 20, PSYDUCK
 	db 15, PSYDUCK
 	db 20, GOLDUCK
 
-	map ROUTE_40
+	map_id ROUTE_40
 	db 6 percent ; encounter rate
 	db 20, TENTACOOL
 	db 15, TENTACOOL
 	db 20, TENTACRUEL
 
-	map ROUTE_41
+	map_id ROUTE_41
 	db 6 percent ; encounter rate
 	db 20, TENTACOOL
 	db 20, TENTACRUEL
 	db 20, MANTINE
 
-	map ROUTE_42
+	map_id ROUTE_42
 	db 4 percent ; encounter rate
 	db 20, GOLDEEN
 	db 15, GOLDEEN
 	db 20, SEAKING
 
-	map ROUTE_43
+	map_id ROUTE_43
 	db 2 percent ; encounter rate
 	db 20, MAGIKARP
 	db 15, MAGIKARP
 	db 10, MAGIKARP
 
-	map ROUTE_44
+	map_id ROUTE_44
 	db 2 percent ; encounter rate
 	db 25, POLIWAG
 	db 20, POLIWAG
 	db 25, POLIWHIRL
 
-	map ROUTE_45
+	map_id ROUTE_45
 	db 2 percent ; encounter rate
 	db 20, MAGIKARP
 	db 15, MAGIKARP
 	db 5, MAGIKARP
 
-	map NEW_BARK_TOWN
+	map_id NEW_BARK_TOWN
 	db 6 percent ; encounter rate
 	db 20, TENTACOOL
 	db 15, TENTACOOL
 	db 20, TENTACRUEL
 
-	map CHERRYGROVE_CITY
+	map_id CHERRYGROVE_CITY
 	db 6 percent ; encounter rate
 	db 20, TENTACOOL
 	db 15, TENTACOOL
 	db 20, TENTACRUEL
 
-	map VIOLET_CITY
+	map_id VIOLET_CITY
 	db 2 percent ; encounter rate
 	db 20, POLIWAG
 	db 15, POLIWAG
 	db 20, POLIWHIRL
 
-	map CIANWOOD_CITY
+	map_id CIANWOOD_CITY
 	db 6 percent ; encounter rate
 	db 20, TENTACOOL
 	db 15, TENTACOOL
 	db 20, TENTACRUEL
 
-	map OLIVINE_CITY
+	map_id OLIVINE_CITY
 	db 6 percent ; encounter rate
 	db 20, TENTACOOL
 	db 15, TENTACOOL
 	db 20, TENTACRUEL
 
-	map ECRUTEAK_CITY
+	map_id ECRUTEAK_CITY
 	db 2 percent ; encounter rate
 	db 20, POLIWAG
 	db 15, POLIWAG
 	db 20, POLIWHIRL
 
-	map LAKE_OF_RAGE
+	map_id LAKE_OF_RAGE
 	db 6 percent ; encounter rate
 	db 15, MAGIKARP
 	db 10, MAGIKARP
 	db 15, GYARADOS
 
-	map BLACKTHORN_CITY
+	map_id BLACKTHORN_CITY
 	db 4 percent ; encounter rate
 	db 15, MAGIKARP
 	db 10, MAGIKARP
 	db 5, MAGIKARP
 
-	map SILVER_CAVE_OUTSIDE
+	map_id SILVER_CAVE_OUTSIDE
 	db 2 percent ; encounter rate
 	db 35, POLIWHIRL
 	db 40, POLIWHIRL
diff --git a/data/wild/kanto_grass.asm b/data/wild/kanto_grass.asm
index e06627d1..ff172097 100644
--- a/data/wild/kanto_grass.asm
+++ b/data/wild/kanto_grass.asm
@@ -1,6 +1,8 @@
 ; Kanto Pokémon in grass
 
-	map DIGLETTS_CAVE
+KantoGrassWildMons:
+
+	map_id DIGLETTS_CAVE
 	db 4 percent, 2 percent, 8 percent ; encounter rates: morn/day/nite
 	; morn
 	db 3, DIGLETT
@@ -27,7 +29,7 @@
 	db 32, DUGTRIO
 	db 32, DUGTRIO
 
-	map MOUNT_MOON
+	map_id MOUNT_MOON
 	db 6 percent, 6 percent, 6 percent ; encounter rates: morn/day/nite
 	; morn
 	db 6, ZUBAT
@@ -54,7 +56,7 @@
 	db 12, CLEFAIRY
 	db 12, CLEFAIRY
 
-	map ROCK_TUNNEL_1F
+	map_id ROCK_TUNNEL_1F
 	db 6 percent, 6 percent, 6 percent ; encounter rates: morn/day/nite
 	; morn
 	db 10, CUBONE
@@ -81,7 +83,7 @@
 	db 15, ZUBAT
 	db 15, ZUBAT
 
-	map ROCK_TUNNEL_B1F
+	map_id ROCK_TUNNEL_B1F
 	db 6 percent, 6 percent, 6 percent ; encounter rates: morn/day/nite
 	; morn
 	db 12, CUBONE
@@ -108,7 +110,7 @@
 	db 15, GOLBAT
 	db 15, GOLBAT
 
-	map VICTORY_ROAD
+	map_id VICTORY_ROAD
 	db 6 percent, 6 percent, 6 percent ; encounter rates: morn/day/nite
 	; morn
 	db 34, GRAVELER
@@ -135,7 +137,7 @@
 	db 40, GRAVELER
 	db 40, GRAVELER
 
-	map TOHJO_FALLS
+	map_id TOHJO_FALLS
 	db 6 percent, 6 percent, 6 percent ; encounter rates: morn/day/nite
 	; morn
 	db 22, ZUBAT
@@ -162,7 +164,7 @@
 	db 23, SLOWPOKE
 	db 23, SLOWPOKE
 
-	map ROUTE_1
+	map_id ROUTE_1
 	db 10 percent, 10 percent, 10 percent ; encounter rates: morn/day/nite
 	; morn
 	db 2, PIDGEY
@@ -189,7 +191,7 @@
 	db 4, HOOTHOOT
 	db 4, HOOTHOOT
 
-	map ROUTE_2
+	map_id ROUTE_2
 	db 10 percent, 10 percent, 10 percent ; encounter rates: morn/day/nite
 	; morn
 	db 3, CATERPIE
@@ -216,7 +218,7 @@
 	db 4, NOCTOWL
 	db 4, NOCTOWL
 
-	map ROUTE_3
+	map_id ROUTE_3
 	db 10 percent, 10 percent, 10 percent ; encounter rates: morn/day/nite
 	; morn
 	db 5, SPEAROW
@@ -243,7 +245,7 @@
 	db 6, CLEFAIRY
 	db 6, CLEFAIRY
 
-	map ROUTE_4
+	map_id ROUTE_4
 	db 10 percent, 10 percent, 10 percent ; encounter rates: morn/day/nite
 	; morn
 	db 5, SPEAROW
@@ -270,7 +272,7 @@
 	db 6, CLEFAIRY
 	db 6, CLEFAIRY
 
-	map ROUTE_5
+	map_id ROUTE_5
 	db 10 percent, 10 percent, 10 percent ; encounter rates: morn/day/nite
 	; morn
 	db 13, PIDGEY
@@ -297,7 +299,7 @@
 	db 14, ABRA
 	db 14, ABRA
 
-	map ROUTE_6
+	map_id ROUTE_6
 	db 10 percent, 10 percent, 10 percent ; encounter rates: morn/day/nite
 	; morn
 	db 13, RATTATA
@@ -324,7 +326,7 @@
 	db 15, RATICATE
 	db 15, RATICATE
 
-	map ROUTE_7
+	map_id ROUTE_7
 	db 10 percent, 10 percent, 10 percent ; encounter rates: morn/day/nite
 	; morn
 	db 17, RATTATA
@@ -351,7 +353,7 @@
 	db 16, ABRA
 	db 16, ABRA
 
-	map ROUTE_8
+	map_id ROUTE_8
 	db 10 percent, 10 percent, 10 percent ; encounter rates: morn/day/nite
 	; morn
 	db 17, SNUBBULL
@@ -378,7 +380,7 @@
 	db 18, KADABRA
 	db 18, KADABRA
 
-	map ROUTE_9
+	map_id ROUTE_9
 	db 10 percent, 10 percent, 10 percent ; encounter rates: morn/day/nite
 	; morn
 	db 15, RATTATA
@@ -405,7 +407,7 @@
 	db 18, RATICATE
 	db 18, RATICATE
 
-	map ROUTE_10_NORTH
+	map_id ROUTE_10_NORTH
 	db 10 percent, 10 percent, 10 percent ; encounter rates: morn/day/nite
 	; morn
 	db 15, SPEAROW
@@ -432,7 +434,7 @@
 	db 16, ELECTABUZZ
 	db 16, ELECTABUZZ
 
-	map ROUTE_11
+	map_id ROUTE_11
 	db 10 percent, 10 percent, 10 percent ; encounter rates: morn/day/nite
 	; morn
 	db 14, HOPPIP
@@ -459,7 +461,7 @@
 	db 16, HYPNO
 	db 16, HYPNO
 
-	map ROUTE_13
+	map_id ROUTE_13
 	db 10 percent, 10 percent, 10 percent ; encounter rates: morn/day/nite
 	; morn
 	db 23, NIDORINO
@@ -486,7 +488,7 @@
 	db 25, QUAGSIRE
 	db 25, CHANSEY
 
-	map ROUTE_14
+	map_id ROUTE_14
 	db 10 percent, 10 percent, 10 percent ; encounter rates: morn/day/nite
 	; morn
 	db 26, NIDORINO
@@ -513,7 +515,7 @@
 	db 28, QUAGSIRE
 	db 28, CHANSEY
 
-	map ROUTE_15
+	map_id ROUTE_15
 	db 10 percent, 10 percent, 10 percent ; encounter rates: morn/day/nite
 	; morn
 	db 23, NIDORINO
@@ -540,7 +542,7 @@
 	db 25, QUAGSIRE
 	db 25, CHANSEY
 
-	map ROUTE_16
+	map_id ROUTE_16
 	db 10 percent, 10 percent, 10 percent ; encounter rates: morn/day/nite
 	; morn
 	db 26, GRIMER
@@ -567,7 +569,7 @@
 	db 30, MUK
 	db 30, MUK
 
-	map ROUTE_17
+	map_id ROUTE_17
 	db 10 percent, 10 percent, 10 percent ; encounter rates: morn/day/nite
 	; morn
 	db 30, FEAROW
@@ -594,7 +596,7 @@
 	db 33, MUK
 	db 33, MUK
 
-	map ROUTE_18
+	map_id ROUTE_18
 	db 10 percent, 10 percent, 10 percent ; encounter rates: morn/day/nite
 	; morn
 	db 26, GRIMER
@@ -621,7 +623,7 @@
 	db 30, MUK
 	db 30, MUK
 
-	map ROUTE_21
+	map_id ROUTE_21
 	db 6 percent, 6 percent, 6 percent ; encounter rates: morn/day/nite
 	; morn
 	db 30, TANGELA
@@ -648,7 +650,7 @@
 	db 28, TANGELA
 	db 28, TANGELA
 
-	map ROUTE_22
+	map_id ROUTE_22
 	db 10 percent, 10 percent, 10 percent ; encounter rates: morn/day/nite
 	; morn
 	db 3, RATTATA
@@ -675,7 +677,7 @@
 	db 7, RATTATA
 	db 7, RATTATA
 
-	map ROUTE_24
+	map_id ROUTE_24
 	db 10 percent, 10 percent, 10 percent ; encounter rates: morn/day/nite
 	; morn
 	db 8, CATERPIE
@@ -702,7 +704,7 @@
 	db 14, GLOOM
 	db 14, GLOOM
 
-	map ROUTE_25
+	map_id ROUTE_25
 	db 10 percent, 10 percent, 10 percent ; encounter rates: morn/day/nite
 	; morn
 	db 10, CATERPIE
@@ -729,7 +731,7 @@
 	db 14, NOCTOWL
 	db 14, NOCTOWL
 
-	map ROUTE_26
+	map_id ROUTE_26
 	db 10 percent, 10 percent, 10 percent ; encounter rates: morn/day/nite
 	; morn
 	db 28, DODUO
@@ -756,7 +758,7 @@
 	db 30, QUAGSIRE
 	db 30, QUAGSIRE
 
-	map ROUTE_27
+	map_id ROUTE_27
 	db 10 percent, 10 percent, 10 percent ; encounter rates: morn/day/nite
 	; morn
 	db 28, DODUO
@@ -783,7 +785,7 @@
 	db 32, NOCTOWL
 	db 32, NOCTOWL
 
-	map ROUTE_28
+	map_id ROUTE_28
 	db 10 percent, 10 percent, 10 percent ; encounter rates: morn/day/nite
 	; morn
 	db 39, TANGELA
diff --git a/data/wild/kanto_water.asm b/data/wild/kanto_water.asm
index 558d56a2..c9abda73 100644
--- a/data/wild/kanto_water.asm
+++ b/data/wild/kanto_water.asm
@@ -1,144 +1,146 @@
 ; Kanto Pokémon in water
 
-	map TOHJO_FALLS
+KantoWaterWildMons:
+
+	map_id TOHJO_FALLS
 	db 4 percent ; encounter rate
 	db 20, GOLDEEN
 	db 20, SLOWPOKE
 	db 20, SEAKING
 
-	map VERMILION_PORT
+	map_id VERMILION_PORT
 	db 2 percent ; encounter rate
 	db 35, TENTACOOL
 	db 30, TENTACOOL
 	db 35, TENTACRUEL
 
-	map ROUTE_4
+	map_id ROUTE_4
 	db 4 percent ; encounter rate
 	db 10, GOLDEEN
 	db 5, GOLDEEN
 	db 10, SEAKING
 
-	map ROUTE_6
+	map_id ROUTE_6
 	db 2 percent ; encounter rate
 	db 10, PSYDUCK
 	db 5, PSYDUCK
 	db 10, GOLDUCK
 
-	map ROUTE_9
+	map_id ROUTE_9
 	db 4 percent ; encounter rate
 	db 15, GOLDEEN
 	db 10, GOLDEEN
 	db 15, SEAKING
 
-	map ROUTE_10_NORTH
+	map_id ROUTE_10_NORTH
 	db 4 percent ; encounter rate
 	db 15, GOLDEEN
 	db 10, GOLDEEN
 	db 15, SEAKING
 
-	map ROUTE_12
+	map_id ROUTE_12
 	db 6 percent ; encounter rate
 	db 25, TENTACOOL
 	db 25, QUAGSIRE
 	db 25, TENTACRUEL
 
-	map ROUTE_13
+	map_id ROUTE_13
 	db 6 percent ; encounter rate
 	db 25, TENTACOOL
 	db 25, QUAGSIRE
 	db 25, TENTACRUEL
 
-	map ROUTE_19
+	map_id ROUTE_19
 	db 6 percent ; encounter rate
 	db 35, TENTACOOL
 	db 30, TENTACOOL
 	db 35, TENTACRUEL
 
-	map ROUTE_20
+	map_id ROUTE_20
 	db 6 percent ; encounter rate
 	db 35, TENTACOOL
 	db 30, TENTACOOL
 	db 35, TENTACRUEL
 
-	map ROUTE_21
+	map_id ROUTE_21
 	db 6 percent ; encounter rate
 	db 35, TENTACOOL
 	db 30, TENTACOOL
 	db 35, TENTACRUEL
 
-	map ROUTE_22
+	map_id ROUTE_22
 	db 2 percent ; encounter rate
 	db 10, POLIWAG
 	db 5, POLIWAG
 	db 10, POLIWHIRL
 
-	map ROUTE_24
+	map_id ROUTE_24
 	db 4 percent ; encounter rate
 	db 10, GOLDEEN
 	db 5, GOLDEEN
 	db 10, SEAKING
 
-	map ROUTE_25
+	map_id ROUTE_25
 	db 4 percent ; encounter rate
 	db 10, GOLDEEN
 	db 5, GOLDEEN
 	db 10, SEAKING
 
-	map ROUTE_26
+	map_id ROUTE_26
 	db 6 percent ; encounter rate
 	db 30, TENTACOOL
 	db 25, TENTACOOL
 	db 30, TENTACRUEL
 
-	map ROUTE_27
+	map_id ROUTE_27
 	db 6 percent ; encounter rate
 	db 20, TENTACOOL
 	db 15, TENTACOOL
 	db 20, TENTACRUEL
 
-	map ROUTE_28
+	map_id ROUTE_28
 	db 2 percent ; encounter rate
 	db 40, POLIWAG
 	db 35, POLIWAG
 	db 40, POLIWHIRL
 
-	map PALLET_TOWN
+	map_id PALLET_TOWN
 	db 6 percent ; encounter rate
 	db 35, TENTACOOL
 	db 30, TENTACOOL
 	db 35, TENTACRUEL
 
-	map VIRIDIAN_CITY
+	map_id VIRIDIAN_CITY
 	db 2 percent ; encounter rate
 	db 10, POLIWAG
 	db 5, POLIWAG
 	db 10, POLIWHIRL
 
-	map CERULEAN_CITY
+	map_id CERULEAN_CITY
 	db 4 percent ; encounter rate
 	db 10, GOLDEEN
 	db 5, GOLDEEN
 	db 10, SEAKING
 
-	map VERMILION_CITY
+	map_id VERMILION_CITY
 	db 6 percent ; encounter rate
 	db 35, TENTACOOL
 	db 30, TENTACOOL
 	db 35, TENTACRUEL
 
-	map CELADON_CITY
+	map_id CELADON_CITY
 	db 2 percent ; encounter rate
 	db 20, GRIMER
 	db 15, GRIMER
 	db 15, MUK
 
-	map FUCHSIA_CITY
+	map_id FUCHSIA_CITY
 	db 2 percent ; encounter rate
 	db 20, MAGIKARP
 	db 15, MAGIKARP
 	db 10, MAGIKARP
 
-	map CINNABAR_ISLAND
+	map_id CINNABAR_ISLAND
 	db 6 percent ; encounter rate
 	db 35, TENTACOOL
 	db 30, TENTACOOL
diff --git a/data/wild/probabilities.asm b/data/wild/probabilities.asm
new file mode 100644
index 00000000..bf3144bb
--- /dev/null
+++ b/data/wild/probabilities.asm
@@ -0,0 +1,18 @@
+mon_prob: MACRO
+; percent, index
+	db \1, \2 * 2
+ENDM
+
+GrassMonProbTable:
+	mon_prob 30,  0 ; 30% chance
+	mon_prob 60,  1 ; 30% chance
+	mon_prob 80,  2 ; 20% chance
+	mon_prob 90,  3 ; 10% chance
+	mon_prob 95,  4 ;  5% chance
+	mon_prob 99,  5 ;  4% chance
+	mon_prob 100, 6 ;  1% chance
+
+WaterMonProbTable:
+	mon_prob 60,  0 ; 60% chance
+	mon_prob 90,  1 ; 30% chance
+	mon_prob 100, 2 ; 10% chance
diff --git a/data/wild/roammon_maps.asm b/data/wild/roammon_maps.asm
new file mode 100644
index 00000000..628a2679
--- /dev/null
+++ b/data/wild/roammon_maps.asm
@@ -0,0 +1,33 @@
+; Maps that roaming monsters can be on, and possible maps they can jump to.
+; Notably missing are Route 40 and Route 41, which are water routes.
+
+roam_map: MACRO
+	map_id \1
+	db _NARG - 1
+rept _NARG - 1
+	map_id \2
+	shift
+endr
+	db 0
+ENDM
+
+RoamMaps:
+; there are NUM_ROAMMON_MAPS entries
+	; start map, ...other maps
+	roam_map ROUTE_29, ROUTE_30, ROUTE_46
+	roam_map ROUTE_30, ROUTE_29, ROUTE_31
+	roam_map ROUTE_31, ROUTE_30, ROUTE_32, ROUTE_36
+	roam_map ROUTE_32, ROUTE_36, ROUTE_31, ROUTE_33
+	roam_map ROUTE_33, ROUTE_32, ROUTE_34
+	roam_map ROUTE_34, ROUTE_33, ROUTE_35
+	roam_map ROUTE_35, ROUTE_34, ROUTE_36
+	roam_map ROUTE_36, ROUTE_35, ROUTE_31, ROUTE_32, ROUTE_37
+	roam_map ROUTE_37, ROUTE_36, ROUTE_38, ROUTE_42
+	roam_map ROUTE_38, ROUTE_37, ROUTE_39, ROUTE_42
+	roam_map ROUTE_39, ROUTE_38
+	roam_map ROUTE_42, ROUTE_43, ROUTE_44, ROUTE_37, ROUTE_38
+	roam_map ROUTE_43, ROUTE_42, ROUTE_44
+	roam_map ROUTE_44, ROUTE_42, ROUTE_43, ROUTE_45
+	roam_map ROUTE_45, ROUTE_44, ROUTE_46
+	roam_map ROUTE_46, ROUTE_45, ROUTE_29
+	db -1 ; end
diff --git a/data/wild/swarm_grass.asm b/data/wild/swarm_grass.asm
index 61d0d853..dd7110e1 100644
--- a/data/wild/swarm_grass.asm
+++ b/data/wild/swarm_grass.asm
@@ -1,7 +1,9 @@
-; swarms in grass
+; Pokémon swarms in grass
+
+SwarmGrassWildMons:
 
 ; Dunsparce swarm
-	map DARK_CAVE_VIOLET_ENTRANCE
+	map_id DARK_CAVE_VIOLET_ENTRANCE
 	db 4 percent, 4 percent, 4 percent ; encounter rates: morn/day/nite
 	; morn
 	db 3, GEODUDE
@@ -29,7 +31,7 @@
 	db 4, DUNSPARCE
 
 ; Yanma swarm
-	map ROUTE_35
+	map_id ROUTE_35
 	db 10 percent, 10 percent, 10 percent ; encounter rates: morn/day/nite
 	; morn
 	db 12, NIDORAN_M
diff --git a/data/wild/swarm_water.asm b/data/wild/swarm_water.asm
index 67751b2b..ec105c00 100644
--- a/data/wild/swarm_water.asm
+++ b/data/wild/swarm_water.asm
@@ -1,4 +1,6 @@
-; swarms in water
+; Pokémon swarms in water
+
+SwarmWaterWildMons:
 
 	; No swarms encountered while surfing in Crystal