There are small numbers on both ends of the wires.
3 is positive, 1 is earth and 2 is unused.
I presume you have a power adapter for your GPS, don't connect these wires directly to your GPS unless it's designed for 12v input. I have a Garmin bare wire power supply (fused), but there's also a Garmin part that is a direct USB connector with no power supply inline... Be careful.
The connector is connected via the ignition circuit.
I'm getting too old for this... Not!
2011 Multistrada (gone to heaven RIP)
2010 Vulcan 900