I get a lot of personal messages about the difference between the Navionics+ cards and Platinum Plus. Guys also ask about the gold cards as well.
The easiest way to answer this question is to say the different cards are all about data overlay. The Platinum Plus and Navionics+ cards have access to the same data except the Platinum card is pre-loaded and the Navionics+ allows you to load and un-load a region. The Navionics+ is not pre-loaded with a region you have to load it onto the www.navionics.com
website, register the card, and then download the region.
The gold card does not have the satellite data overlay or 3d. You can find more details by going here: http://www.navionics.com/en/marine-lakes-charts-1