Just fitted some new props to my little drone, so out to the park for a test flight. I figured it was an ideal opportunity to prove a point I made earlier about telling height and location of a drone from a photograph.
what i done was zoom and snap a photograph of the local comunity hospital from the park,
then from the exact same height and postition took a 360 pano.
I have cropped the photograph too, but you see how difficult it is to tell my height and position from the single shot, the pano gives you a much better idea as you have more reference points.
I promise both shots are from the same same location and both are from a height of 50m
The only way to tell a drone’s position from a picture is if it is looking straight down. Height would still have to be an estimate as fields of view of different lenses on different drones will give different impressions of altitude.
As Mr MPW seems fond of saying - ask five pilots on the ground how high a passing aircraft is and you will get ten different answers; the first five what each pilot thinks, the second five as each pilot revise his estimate in the light of the other four pilots first answers.
The only way to tell where you were in the first picture is to look at your aircraft flight logs, trim the parkland off the bottom and hey - you’re flying over a built up area!
If you know all the factors it is simple trigonometry, for sure. My point was that if you don’t know anything other than it is a drone photo it isn’t possible to give more than, at best, an educated guess.
I was thinking about this when walking the dog this morning in connection with the long-running National Trust threads.
I can take a picture of an NT property from outside their boundary with my inspire using a 12mm lens or a 45 - 25mm equivalent being 24mm wide to 90mm short tele, Get my act together and fire up one of my big gimbals and a Droidwork Octocopter and I can fly a full frame - or better yet a micro four thirds with a 500 mirror.
Publish the pictures and wait for the NT to start writing letters …
I just learned something really epic, i wondered how you would get the focal legnth, I know you cant do this from facebook but this forum actually gives lots of info when you down load a pic. I downloaded my image then went to properties and got alsorts of stuff, even the GPS location. I still argue with the height though I was at 50M not 61, but the location is bang on.
To view exif data, any software designed to view exif data. Even a hex editor will do the job if you prefer that. Exiftool is the industry standard but as I said there are dozens of tools and it’s there in plain text for you to read.
