Hi
I would like to offer my service to build this app for you.
I have experience with DJI SDK and I have built flight automation app for DJI drones. My app was used to automate mobile communication tower inspection using Phantom 3, Phantom 4, Inspire 1 and Inspire 2.
I have also developed another application which has similar features of Pix4D capture. It features rectangular single missions, double missions, circular missions, free waypoint missions etc.
I also have experience in developing desktop applications mainly using C, C++ and Python. My primary development environment is Linux and I have developed a video streaming application for a car manufacturer in India on Raspberry PI boards. It was later upgraded by myself to NVIDIA Jetson TK1 boards.
I can deliver you best results well within time and budget. Please message me to take this further.
Thanks and Regards,
Gurjap Singh