User data exported from later model Garmin GPSmap marine GPS sets consists of ADM files written to a VFAT-formatted SD card.
This data includes user-generated waypoints and routes, and recorded GPS tracks.
adm2gpx converts this data to industry-standard GPX records that may be imported into third-party mapping and GPS software.
Superb little tool, worked on a very large dataset and produced accurate repeatable results. VERY useful. Thank you!