Hi Steve, if I got this right, the NOD file format is not designed to be read sequentially, at least not the NOD 1 part. My understanding is this: We write one NOD 1 section for each RouteCenter instance. The offset to the beginning of such a section is only (?) stored in NET, and it is difficult to calculate it. All offsets to nodes are stored in NOD 2, except for the 1st ones, which are stored in NET only(?). Is this true for all maps? If yes, NodDisplay should rather use these offsets to display NOD 1 data, this would avoid lines like 00001334 | 0012a7 | f2 | low f2 | | | lost sync calc-end=4fcd, should be=2bcd and 0000c950 | 00c8c3 | 00 | low 0 | | | spurious 0? | | | | | | New node 0000c951 | 00c8c4 | 00 | low 0 | | | spurious 0? | | | | | | New node If you agree I'll create a patch to implement that. Gerd