Touch Screen Units - Map not moving as you move.
Without realising you may have touched & moved (panned) the screen.
If you see the white back arrow symbol at the bottom of the map page rather than the white cross, touch the back arrow and your map will be back to your location and will move under the position indicator.
What are the best Map options for a Garmin Handheld GPS Device - Video here
We have many more tips and training videos to get you going with your Garmin Handheld GPS device and Garmin's Basecamp planning software on our Online Training Resource - More info here
Buy and learn from the experts - GPS Training