diff --git a/src/tilearea.cpp b/src/tilearea.cpp
new file mode 100644
--- /dev/null
+++ b/src/tilearea.cpp
@@ -0,0 +1,97 @@
+/* $Id$ */
+
+/*
+ * This file is part of OpenTTD.
+ * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
+ * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/** @file tilearea.cpp Handling of tile areas. */
+
+#include "stdafx.h"
+
+#include "tile_map.h"
+#include "core/math_func.hpp"
+#include "tilearea_type.h"
+
+/**
+ * Construct this tile area based on two points.
+ * @param start the start of the area
+ * @param end   the end of the area
+ */
+TileArea::TileArea(TileIndex start, TileIndex end)
+{
+	uint sx = TileX(start);
+	uint sy = TileY(start);
+	uint ex = TileX(end);
+	uint ey = TileY(end);
+
+	if (sx > ex) Swap(sx, ex);
+	if (sy > ey) Swap(sy, ey);
+
+	this->tile = TileXY(sx, sy);
+	this->w    = ex - sx + 1;
+	this->h    = ey - sy + 1;
+}
+
+/**
+ * Add a single tile to a tile area; enlarge if needed.
+ * @param to_add The tile to add
+ */
+void TileArea::Add(TileIndex to_add)
+{
+	if (this->tile == INVALID_TILE) {
+		this->tile = to_add;
+		this->w = 1;
+		this->h = 1;
+		return;
+	}
+
+	uint sx = TileX(this->tile);
+	uint sy = TileY(this->tile);
+	uint ex = sx + this->w - 1;
+	uint ey = sy + this->h - 1;
+
+	uint ax = TileX(to_add);
+	uint ay = TileY(to_add);
+
+	sx = min(ax, sx);
+	sy = min(ay, sy);
+	ex = max(ax, ex);
+	ey = max(ay, ey);
+
+	this->tile = TileXY(sx, sy);
+	this->w    = ex - sx + 1;
+	this->h    = ey - sy + 1;
+}
+
+/**
+ * Does this tile area intersect with another?
+ * @param ta the other tile area to check against.
+ * @return true if they intersect.
+ */
+bool TileArea::Intersects(const TileArea &ta) const
+{
+	if (ta.w == 0 || this->w == 0) return false;
+
+	assert(ta.w != 0 && ta.h != 0 && this->w != 0 && this->h != 0);
+
+	uint left1   = TileX(this->tile);
+	uint top1    = TileY(this->tile);
+	uint right1  = left1 + this->w - 1;
+	uint bottom1 = top1  + this->h - 1;
+
+	uint left2   = TileX(ta.tile);
+	uint top2    = TileY(ta.tile);
+	uint right2  = left2 + ta.w - 1;
+	uint bottom2 = top2  + ta.h - 1;
+
+	return !(
+			left2   > right1  ||
+			right2  < left1   ||
+			top2    > bottom1 ||
+			bottom2 < top1
+		);
+}
+