Placing a map in a item frame saves your location on the map, even if you haven't added a compass. The marker does not move even if you move around and every time you add another copy of that map in an item frame, it adds another marker. Removing the map from the item frame removes the marker. And I DID NOT add a compass just for clarification.
How to reproduce: In creative, make a map (do not add anything to it). Place the map in an item frame. A marker should pop up.
Note:I have not tested this in survival.
Look at the screenshots below. They really help show what I am saying. Note: they are in reverse order.