Hey, next week I would like to take a flight with the Phantom 2 Vision in a major city (but away from people as I plan to fly at night). What I wonder about is the compass calibration. In the manual it is said to stay far away from big buildings while calibrating because its steel structure might interfere with the compass. What would you recommend to me? Is it safe to fly, if the compass calibration works successfully (meaning no red or yellow light at the end of the procedure) although there were bug buildings all around me? Or might it be better to calibrate it on a field 30km away from the city, take it to the city and fly it without recalibrating? I am afraid to fly the phantom without recalibrating it before every single takeoff. What would you do if you were me regarding the compass calibration? Thank you!