The Factory's auxiliary power socket is not like the usual cig lighter socket. It's a "Powerlet" socket like these:
Powerlet also market a short extension leads that connect to their socket and terminate in one or two normal cig lighter type sockets:
The position of the Factory's socket, just under the tank, is not the most convenient place to connect a GPS. It's OK for heated clothing and that sort of thing. A lot of members have chosen to provide a separate supply for the GPS from a place that's ignition switch controlled, that is it comes on and off with the ignition, like the wire that feeds the tiny position lamp in the headlight.