diff -r 96b4b92b86ae -r 9c3129cb019b src/tile.cpp
--- a/src/tile.cpp	Wed Jan 10 18:44:52 2007 +0000
+++ b/src/tile.cpp	Wed Jan 10 18:56:51 2007 +0000
@@ -16,7 +16,7 @@
 
 	if (TileX(tile) == MapMaxX() || TileY(tile) == MapMaxY()) {
 		if (h != NULL) *h = 0;
-		return 0;
+		return SLOPE_FLAT;
 	}
 
 	min = a = TileHeight(tile);
@@ -35,7 +35,7 @@
 
 	if (h != NULL) *h = min * TILE_HEIGHT;
 
-	return r;
+	return (Slope)r;
 }
 
 uint GetTileZ(TileIndex tile)