Whose ad was this? The Humminbird website says "GPS Chartplotting with built-in ContourXD mapping". I haven't looked at much of the ContourXD map, but what I have seen does look like Mapquest. The Navionics maps are a separately purchased SD card that you load in one of the SD card slots. If you actually bought a unit that included the Navionics map card and you don't have it, talk to your retailer. If you buy one, check out the Navionics website first. The Humminbird site has a link. There are various versions, such as Premium and Platinum. Check the lake listings for each so you know if your favorite lakes are included.
Ron.