diff --git a/Source/Game/Maps/GridDefines.cs b/Source/Game/Maps/GridDefines.cs
index 2fbdc45da..419c8a888 100644
--- a/Source/Game/Maps/GridDefines.cs
+++ b/Source/Game/Maps/GridDefines.cs
@@ -86,6 +86,13 @@ namespace Game.Maps
             return new GridCoord(x_val, y_val);
         }
 
+        public static GridCoord ComputeGridCoordSimple(float x, float y)
+        {
+            int gx = (int)(MapConst.CenterGridId - x / MapConst.SizeofGrids);
+            int gy = (int)(MapConst.CenterGridId - y / MapConst.SizeofGrids);
+            return new GridCoord((uint)((MapConst.MaxGrids - 1) - gx), (uint)((MapConst.MaxGrids - 1) - gy));
+        }
+
         public static CellCoord ComputeCellCoord(float x, float y)
         {
             double x_offset = ((double)x - MapConst.CenterGridCellOffset) / MapConst.SizeofCells;
diff --git a/Source/Game/Maps/GridMap.cs b/Source/Game/Maps/GridMap.cs
index ac79fc4e5..7952ff7f6 100644
--- a/Source/Game/Maps/GridMap.cs
+++ b/Source/Game/Maps/GridMap.cs
@@ -480,7 +480,7 @@ namespace Game.Maps
             if (_minHeightPlanes == null)
                 return -500.0f;
 
-            GridCoord gridCoord = GridDefines.ComputeGridCoord(x, y);
+            GridCoord gridCoord = GridDefines.ComputeGridCoordSimple(x, y);
 
             int doubleGridX = (int)(Math.Floor(-(x - MapConst.MapHalfSize) / MapConst.CenterGridOffset));
             int doubleGridY = (int)(Math.Floor(-(y - MapConst.MapHalfSize) / MapConst.CenterGridOffset));