I mentioned this in another thread but I decided to break it out into its own topic.
I've been looking at DroneDeploy but the app requires an internet connection before launching. If you need to do offline mapping can load your flightplans and then drive/fly outside of internet/cellular range to your site but you will lose your flightplan data if the app crashes or your mobile device battery dies. I need a stand-alone, offline app that I can fire up in the field where there is not wifi or cellular connection and fly with previously downloaded flightplans. DroneDeploy says they're working on that feature but is anyone aware of an app that does this specifically for shooting mapping images (sets up a transect grid, computes overlap, automatically snaps images)? The images will be stitched together later with DroneDeploy, once I'm back in civilization.

Details: I'm flying a P4P with android mobile devices  (Nvidia Shield and Nexus 5)

Thanks!

I am using a Nexus 7 2nd gen tablet with no cellualar. With Litchi you pre plan your flight, and load it when ready to fly. I have also wrote missions on my desk top and copied to my tablet. Litchi works flawlessly with no cellular and aircraft connected through wifi. Note you will need a tablet with a built in GPS if you want to see maps during flight.

The Dji GS Pro does what you are looking for. Unfortunately it is only available for ios tablets. http://www.dji.com/ground-station-pro