Size at zoom level0 : 200 x 150
Size at zoom level1 : 200 x 150
Size at zoom level2 : 200 x 149
-Size at zoom level3 : 200 x 149
-Size at zoom level4 : 200 x 149
+Size at zoom level3 : 199 x 149
+Size at zoom level4 : 199 x 149
Size at zoom level5 : 200 x 149