Example, GPS trackers which can track the activities of the vehicle(speed, direction, location etc.) beyond our line of sight.

Here "Visibility" is used metaphorically. Something which is physically not visible but can be monitored as if it is present in our line of sight(using technology) Example, GPS trackers fixed in vehicle can track the activities of the vehicle(speed, direction, location etc.) beyond our line of sight. Even though vehicle is not physically present in front of our eyes, we can keep track on movements.

For example, something which is not present in front of our eyes but still keep eye or track the movement of a material.

Example, GPS trackers which can track the activities of the vehicle(speed, direction, location etc.) beyond our line of sight.