When in use, the GP-E1 Receiver* will automatically record the geographical information (latitude, longitude, altitude, and Universal Coordinated Time (UTC)) of videos and photos. Detecting altitude is even possible from inside an airplane or helicopter.
There's also a built-in electronic compass that can accurately detect the cardinal direction in which the photographer is facing - even if the EOS-1D X is held vertically, the GP-E1 can still record the proper positioning from when it was in a normal position.
*In certain countries and regions, the use of GPS may be restricted. Therefore, be sure to use GPS in accordance with the laws and regulations of your country or region. Be particularly careful when traveling outside your home country.
As a signal is received from GPS satellites, take sufficient measures when using in locations where the use of electronics is regulated.