There are two modes in any Sendero powered GPS system. GPS mode and Virtual mode. GPS mode is when you are tracking with the receiver and virtual mode is where you can explore the map without being connected to the satellites. Just load the appropriate map and virtually explore. Sendero Group "The GPS company:" Featuring Sendero GPS on the BrailleNote, the Sense Nav, on Windows phones with Mobile Geo and coming soon with StreetTalk VIP for the Pac Mate. Distributing Trekker Breeze and Wayfinder for Symbian phones. Also distributing Victor Stream, KNFB Mobile Reader, Talks, Mobile Speak, Tiger embossers, Miniguide and ID Mate