Canon EOS-1D X Mark II DSLR Camera (Body Only) - Manual (Page 226)

Logging the Route Traveled
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When connecting the camera to a computer, use the provided interface
cable or one from Canon (p.487). When connecting the interface cable,
use the provided cable protector (p.38).
The GPS antenna is located at the top of the camera body. For this
reason, even when carrying the camera, such as in a bag, try to keep the
top of the camera facing upwards, and do not place anything on top of it.
Set the camera time and date as accurately as possible. Also, set correct
time zone and daylight saving time for the shooting location.