Downloadable BirdEye-Format Maps
Pro-level subscribers can preload CalTopo's high quality map layers onto their GPS and be prepared wherever they go. These JNX formatted maps are compatible with Garmin GPSs that support BirdsEye(TM) imagery, such as the 62s, 64s, and most touchscreen models. However, you must unlock your GPS so that it will work with 3rd party maps not sanctioned by Garmin.
Because the JNX format does not support transparency, maps come in several pre-set combinations:
Coverage for named JNX files can be located on these maps: USGS / Slope Angle Shading and Aerial Imagery. Some newer files dropped the named-area convention in favor of having each file cover a 1 degree by 1 degree grid. These are named based on the southeast corner; 42x111 covers everything between 42 and 43 degrees of latitude, and 111 to 112 degrees of longitude.
To get started, just go to the downloads tab on your account dialog, and then click on a specific link.
Some sample screenshots: