After reading the livescope beam thread that shows the beam on map, I immediately thought that the Garmin techs should come up with an update to show a transparent trail that would show up on the map when using side imaging.
What I mean by this is if you are side imaging and have your unit set to 80 feet while idling it would cover the map 80 feet on each side in a color that does not take away the contour lines. By doing this you could see where your new path could be so you don’t scan the same bottom as the previous scan.