Hi Gerd, I have found out that the levels in the option file matters: These settings are fine if I skip level 23: levels = 0:24, 1:22, 2:20, 3:18 overview-levels = 4:17, 5:15, 6:14 These go wrong, the gmap file is not compiled: levels = 0:24, 1:23, 2:22, 3:20, 4:18 overview-levels = 5:17, 6:15, 7:14 Now I have tried 3312 instead of 6628 for the second highest level 23: x-dem-dists: 3312,3312,9942,13248,44176 Then I got this error: SEVERE (BlockManager): splitter\49000245.o5m: overflowed directory with max block 65534, current=65535 SEVERE (MapFailedException): splitter\49000245.o5m: (thrown in BlockManager.allocate()) Too many blocks. Use a larger block size with an option such as --block-size=1024 or --block-size=2048 Exception in thread "main" java.lang.NegativeArraySizeException at uk.me.parabola.mkgmap.reader.hgt.HGTConverter. If I use x-dem-dists: 3312,9942,9942,13248,44176 No error but not rendered and no gmap. If I use x-dem-dists: 9942,9942,9942,13248,44176 Everything is ok. So maybe I had a wrong values for level 23 which seems fixed by r-4066?