I've been attempting to extract track information from Humminbird (Side Imaging Sonar) binary files and have hit a stumbling block with the coordinates it provides. The values are apparently in Mercator meters but no UTM zone is supplied in the output. I would like to know if anyone knows of a mercator meter conversion that doesn't require a UTM zone, and if so how do you do it? I've found one conversion which kind of does the job but not acurately enough (http://www.oziexplorer3.com/eng/eagle.html).
So basically I get the numbers Lon: 16226043 Lat: -4557743. I know these should convert to 145.75528834210039 and -38.032398555522214 but can't work out how.
I've had a discussion about this issue on a more dedicated forum but came to a dead end (http://forums.sideimagingsoft.com/index.php?topic=5623.msg35417). I could be reading the binary section wrong but all other data in the line comes out fine.