Are you using MapPilot? It does an amazing job creating those kinds of maps with color elevation overlay in high resolution.
Currently I only have Phantom 2 (not even the "vision" version), so I cannot control the drone from cellphone app (to do that I'd have to buy the lightbridge for Phantom 2, and replace control receiver with 5.8 GHz one, so it's like buying new drone). I'm flying the drone by hand.
It is true that an app would do it more efficient than me.
Also there is no need to stay in communication contact during the mission.
Hm, I didn't knew that; from all the specs I read I was sure that the drone cannot store the flight path and then disconnect from controller... Are you sure about this?