diff --git a/OpenRA.Game/Map/Map.cs b/OpenRA.Game/Map/Map.cs
index 2f578880cd..3f3f45a160 100644
--- a/OpenRA.Game/Map/Map.cs
+++ b/OpenRA.Game/Map/Map.cs
@@ -767,6 +767,9 @@ namespace OpenRA
 
 		bool ContainsAllProjectedCellsCovering(MPos uv)
 		{
+			if (MaximumTerrainHeight == 0)
+				return Contains((PPos)uv);
+
 			foreach (var puv in ProjectedCellsCovering(uv))
 				if (!Contains(puv))
 					return false;