Add Maps
GPSMAP 64st comes with a built-in worldwide basemap with shaded relief, preloaded TOPO 100K and a 1-year subscription of BirdsEye Satellite Imagery for a photo-realistic view. Adding more maps is easy with our array of detailed topographic, marine and road maps. With 8 GB of onboard memory and microSD™ card slot, you can conveniently download TOPO 24K maps and hit the trail, plug in BlueChart® g2 preloaded cards for a great day on the water or City Navigator NT® map data for turn-by-turn routing on roads (see maps tab for compatibility). In addition, the 64st is compatible with Garmin Custom Maps, a map format that allows you to transform paper and electronic maps easily into downloadable maps for your device, for free.
Most all of Garmin GPS only use Garmin Maps... That may change in the future as they have bought Navionics...