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Routes and Tracks
Trail Tech Voyager Moto-GPS. This demonstration tutorial shows how to follow along a route while recording a track. Specifically: copy a GPX file onto a MicroSD card, import it into Voyager, start logging a track, follow along the gray route lines while logging a black track line, then stop logging and export the track to the MicroSD card as a GPX file.
You have to pay attention to the notes shown as text in the video. They note in the video that the streets have been recorded in OSM and imported via a GPX file.