I just got a dragonfly 4pro with the navionics + package. I can't for the life of me get the navionics to work I guess. I can pull up the 3 different maps but when I try to look at contours of the lake it shows absolutely nothing just a very undetailed blue block of a lake/river. Do I need to download and register the card on a computer to get the detailed maps? 

Did you register the card and do an update adding the Sonar Charts for the bodies of water you want the extra data for?

 

There are thousands of bodies of water that have not been surveyed by any company to have contour mapping. One may be your favorite.

 

You can view the current maps on the Navionics website's Web App. Any map you see, can be on your card if you update it.

I have not because I don't have a computer to do it with. I've tried looking at Lake Ontario I'm pretty sure the Great Lakes have been mapped. 

I got it figured out now to learn to read and interpret the sonar and down imaging.