Hey Bill, thanks for posting. I’m a consultant (civil engineer) in Brevard so it’s good to see SJRWMD getting into the use of drones. They’re a great tool, and we use them for almost all of our current engineering projects. We use a Phantom 4 Pro and process in Pix4D. Since almost all of our projects involve a surveyor, we have the benefit of using very accurate GCPs for processing our imagery.
As you might know already, the altitude readings are based on barometric pressure. They’re going to be relative readings, meaning that even if you calibrate the drone before flight, the altitude is