I have been geotagging my images for a few years. With the Hasselblad and Nikon, it requires a piece of gear hanging off your camera. The EM-1 has a really nifty feature for use with your iPhone. You load the OI.Share app go through a little syncing fiddle between camera and phone and you are away.
You get geotagged files straight out of the camera so there is no intermediate step between card and computer.