diff --git a/src/map.cpp b/src/map.cpp
index ba6c82dbaa..8e7aeffed6 100644
--- a/src/map.cpp
+++ b/src/map.cpp
@@ -8,6 +8,7 @@
 #include "core/alloc_func.hpp"
 #include "core/math_func.hpp"
 #include "map_func.h"
+#include "tile_map.h"
 
 #if defined(_MSC_VER)
 /* Why the hell is that not in all MSVC headers?? */
@@ -327,3 +328,59 @@ bool CircularTileSearch(TileIndex *tile, uint radius, uint w, uint h, TestTileOn
 	*tile = INVALID_TILE;
 	return false;
 }
+
+/*!
+ * Finds the distance for the closest tile with water/land given a tile
+ * @param tile  the tile to find the distance too
+ * @param water whether to find water or land
+ * @return distance to nearest water (max 0x7F) / land (max 0x1FF; 0x200 if there is no land)
+ * @note FAILS when an industry should be seen as water
+ */
+uint GetClosestWaterDistance(TileIndex tile, bool water)
+{
+	if (IsTileType(tile, MP_WATER) == water) return 0;
+
+	uint max_dist = water ? 0x7F : 0x200;
+
+	int x = TileX(tile);
+	int y = TileY(tile);
+
+	uint max_x = MapMaxX();
+	uint max_y = MapMaxY();
+	uint min_xy = _settings_game.construction.freeform_edges ? 1 : 0;
+
+	/* go in a 'spiral' with increasing manhattan distance in each iteration */
+	for (uint dist = 1; dist < max_dist; dist++) {
+		/* next 'diameter' */
+		y--;
+
+		/* going counter-clockwise around this square */
+		for (DiagDirection dir = DIAGDIR_BEGIN; dir < DIAGDIR_END; dir++) {
+			static const int8 ddx[DIAGDIR_END] = { -1,  1,  1, -1};
+			static const int8 ddy[DIAGDIR_END] = {  1,  1, -1, -1};
+
+			int dx = ddx[dir];
+			int dy = ddy[dir];
+
+			/* each side of this square has length 'dist' */
+			for (uint a = 0; a < dist; a++) {
+				/* MP_VOID tiles are not checked (interval is [min; max) for IsInsideMM())*/
+				if (IsInsideMM(x, min_xy, max_x) && IsInsideMM(y, min_xy, max_y)) {
+					TileIndex t = TileXY(x, y);
+					if (IsTileType(t, MP_WATER) == water) return dist;
+				}
+				x += dx;
+				y += dy;
+			}
+		}
+	}
+
+	if (!water) {
+		/* no land found - is this a water-only map? */
+		for (TileIndex t = 0; t < MapSize(); t++) {
+			if (!IsTileType(t, MP_VOID) && !IsTileType(t, MP_WATER)) return 0x1FF;
+		}
+	}
+
+	return max_dist;
+}
diff --git a/src/map_func.h b/src/map_func.h
index 932e2f8fda..038942cd96 100644
--- a/src/map_func.h
+++ b/src/map_func.h
@@ -431,4 +431,9 @@ static inline TileIndex RandomTileSeed(uint32 r)
  */
 #define RandomTile() RandomTileSeed(Random())
 
+/**
+ * Finds the distance for the closest tile with water/land given a tile
+ */
+uint GetClosestWaterDistance(TileIndex tile, bool water);
+
 #endif /* MAP_FUNC_H */
diff --git a/src/newgrf_industries.cpp b/src/newgrf_industries.cpp
index a0df59d8f2..34a6f89757 100644
--- a/src/newgrf_industries.cpp
+++ b/src/newgrf_industries.cpp
@@ -38,62 +38,6 @@ IndustryType MapNewGRFIndustryType(IndustryType grf_type, uint32 grf_id)
 	return _industry_mngr.GetID(GB(grf_type, 0, 6), grf_id);
 }
 
-/**
- * Finds the distance for the closest tile with water/land given a tile
- * @param tile  the tile to find the distance too
- * @param water whether to find water or land
- * @return distance to nearest water (max 0x7F) / land (max 0x1FF; 0x200 if there is no land)
- * @note FAILS when an industry should be seen as water
- */
-static uint GetClosestWaterDistance(TileIndex tile, bool water)
-{
-	if (IsTileType(tile, MP_WATER) == water) return 0;
-
-	uint max_dist = water ? 0x7F : 0x200;
-
-	int x = TileX(tile);
-	int y = TileY(tile);
-
-	uint max_x = MapMaxX();
-	uint max_y = MapMaxY();
-	uint min_xy = _settings_game.construction.freeform_edges ? 1 : 0;
-
-	/* go in a 'spiral' with increasing manhattan distance in each iteration */
-	for (uint dist = 1; dist < max_dist; dist++) {
-		/* next 'diameter' */
-		y--;
-
-		/* going counter-clockwise around this square */
-		for (DiagDirection dir = DIAGDIR_BEGIN; dir < DIAGDIR_END; dir++) {
-			static const int8 ddx[DIAGDIR_END] = { -1,  1,  1, -1};
-			static const int8 ddy[DIAGDIR_END] = {  1,  1, -1, -1};
-
-			int dx = ddx[dir];
-			int dy = ddy[dir];
-
-			/* each side of this square has length 'dist' */
-			for (uint a = 0; a < dist; a++) {
-				/* MP_VOID tiles are not checked (interval is [min; max) for IsInsideMM())*/
-				if (IsInsideMM(x, min_xy, max_x) && IsInsideMM(y, min_xy, max_y)) {
-					TileIndex t = TileXY(x, y);
-					if (IsTileType(t, MP_WATER) == water) return dist;
-				}
-				x += dx;
-				y += dy;
-			}
-		}
-	}
-
-	if (!water) {
-		/* no land found - is this a water-only map? */
-		for (TileIndex t = 0; t < MapSize(); t++) {
-			if (!IsTileType(t, MP_VOID) && !IsTileType(t, MP_WATER)) return 0x1FF;
-		}
-	}
-
-	return max_dist;
-}
-
 /** Make an analysis of a tile and check for its belonging to the same
  * industry, and/or the same grf file
  * @param tile TileIndex of the tile to query