I operate drones in Canada. I would suggest a Phantom 3 'Professional'.
It will give you a decent range compared to the other versions of the
Phantom 3 ('Standard','Advanced', and '4k'), since it uses Lightbridge for
it's control link and video feedback. Since it's 2 generations old you
will be able to find them relatively cheaply. You could use any small
drone as long as it's camera is GPS enabled and it's sending the video back
to the pilot. That being said, the Mavic is a much better machine for a
good price. Really small size for what it does and has a better flight
time which would be helpful for your case. But twice the price of a P3Pro.
I envision your workflow to be:
1. Fly the drone around the perimeter of the area you are mapping, taking
pictures all the way around. Use the downward facing camera to ensure you
are positioned properly.
2. Use one of QGIS' extensions to import the pictures and create a point
3. Transform using the points to polygons and you've got your areas.
Should work well.
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