If you are using an external gps(bad elf or Garmin GLO) with an apple wi fi only iPad and want to use your off line maps there is a serious issue with the most recent iOS 8.3 update. Your gps will connect to your iPad but it will not transfer location data. Numerous posts online....which I dicovered after doing a software update to 8.3. My bad. I know better. I now cannot get gps data for over 40 gigs of map data I have downloaded. None of my navigation apps work (HD, garmin, Trimble, Gaia) Do not update to the newest software until there is a fix from Apple. Many folks unhappy, particularly pilots who rely on this setup for navigation.