From what I'm seeing .... the Garmin 7sv does not have any actual "map", just a white background that you can set a waypoint on to return to, but not a "base map" (blue area designating water). If it doesn't have a map chip slot, then mapping capabilities are absent.

Here's what they consider your GPS mapping capability :



And, also .... according to the Garmin webpage, this unit is "discontinued".