OSM Map On Garmin/Garmin Common Header
A reverse-engineering of Garmin's Common Header
The structure of the common header is the same in all Garmin subfiles.
| Byte Offset | Length (bytes) | Description |
|---|---|---|
| 0x000 | 10 | ID-String (depends on the type of the subfile in question, but always of the form "GARMIN XXX" where XXX is the file-extension of that subfile. |
| 0x00A | 1 | typically 0x01 (major part of file's version number?) |
| 0x00B | 1 | typically 0x00 (minor part of file's version number?) |
| 0x00C | 2 | Creation year |
| 0x00E | 1 | Creation month |
| 0x00F | 1 | Creation day |
| 0x010 | 1 | Creation hour |
| 0x011 | 1 | Creation minute |
| 0x012 | 1 | Creation second |