Transferring Maps from Garmin SD Card to BaseCamp?

Hi Everyone,

I purchased a set of TOPO maps form Garmin which are on the SD card.

When I plug in my 62s, I see BaseCamp uploading the map. When I unplug the GPS, the maps disappear from BaseCamp. I would like to to view these maps regardless of whether the GPS is plugged in or not.

Is this possible? If so, how?