diff --git a/include/constants/ground_map.h b/include/constants/ground_map.h
index 89c436ad2..34467dda0 100644
--- a/include/constants/ground_map.h
+++ b/include/constants/ground_map.h
@@ -233,4 +233,9 @@ enum {
     MAP_COUNT,
 };
 
+// These are automatically adjusted via GetAdjustedGroundMap.
+#define MAP_TEAM_BASE           MAP_TEAM_BASE_PIKACHU_BASIC
+#define MAP_TEAM_BASE_INSIDE    MAP_TEAM_BASE_INSIDE_PIKACHU_BASIC
+#define TEAM_BASE_MAPS_PER_SPECIES 6 // 3 on the inside and 3 on the outside (basic, construction, final)
+
 #endif // GUARD_CONSTANTS_GROUND_MAP_H
diff --git a/include/data_script.h b/include/data_script.h
index ee7cf97ec..a7458c063 100644
--- a/include/data_script.h
+++ b/include/data_script.h
@@ -1,6 +1,7 @@
 #include "ground_script.h"
 #include "event_flag.h"
 #include "constants/item.h"
+#include "constants/ground_map.h"
 #define LPARRAY(x) (sizeof(x)/sizeof(*(x))), x
 
 #define CPOS_HALFTILE 0x2
diff --git a/include/ground_map.h b/include/ground_map.h
index 5d35c3ee3..35c2ec7f3 100644
--- a/include/ground_map.h
+++ b/include/ground_map.h
@@ -2,10 +2,10 @@
 #define GUARD_GROUND_MAP_H
 
 void GroundMap_Reset(void);
-
 void AllocGroundMapAction(void);
 void FreeGroundMapAction(void);
 void sub_80A4B38(void);
 void sub_80A4B54(void);
+s16 GetAdjustedGroundMap(s32 mapId);
 
 #endif // GUARD_GROUND_MAP_H
diff --git a/src/ground_map.c b/src/ground_map.c
index d3380ba19..fdbe3fbe1 100644
--- a/src/ground_map.c
+++ b/src/ground_map.c
@@ -184,26 +184,21 @@ bool8 sub_80A4D48(s16 index)
     return FALSE;
 }
 
-s32 GetAdjustedGroundMap(s16 param_1)
+s16 GetAdjustedGroundMap(s32 mapId)
 {
-    s32 iVar5;
+    s32 retMapId = (s16) mapId;
 
-    iVar5 = param_1;
-
-    switch(iVar5)
-    {
-        case 9:
-        case 0xC:
-            iVar5 = (s16)(iVar5 + ((GetScriptVarValue(NULL, BASE_KIND) * 6) + GetScriptVarValue(NULL, BASE_LEVEL)));
+    switch (retMapId) {
+        case MAP_TEAM_BASE:
+        case MAP_TEAM_BASE_INSIDE:
+            retMapId = (s16)(retMapId + ((GetScriptVarValue(NULL, BASE_KIND) * TEAM_BASE_MAPS_PER_SPECIES) + GetScriptVarValue(NULL, BASE_LEVEL)));
             break;
-        case 2:
+        case MAP_WHISCASH_POND:
             if (sub_80023E4(6)) {
-                iVar5 = 3;
+                retMapId = MAP_WHISCASH_POND_OPEN;
             }
             break;
-        default:
-            break;
     }
 
-    return iVar5;
+    return retMapId;
 }
diff --git a/src/ground_script.c b/src/ground_script.c
index 547374bc8..b7ab60f1c 100644
--- a/src/ground_script.c
+++ b/src/ground_script.c
@@ -108,7 +108,6 @@ void sub_809D1E4(s32, s32, s32);
 void sub_809D208(s32, PixelPos*, s32);
 void sub_809D220(s32, s32, s32);
 void GroundScriptLockJumpZero(s16);
-s16 GetAdjustedGroundMap(s32);
 void sub_80A87AC(s32, s32);
 void sub_80A8BD8(s16, s32*);
 u32 sub_80A8C2C();