I absolutely believe you measured it well in real world, what I am saying is that the shape of the object in 3D space of RC might not be the exact same and therefore taking that into account is not very good. Regarding the drones, I do not have an experience with drones myself and can’t give an exact statement to this, but I know that you should prevent having ultra wide angle lens and you can check the accuracy of the drones gps on their site somewhere. The small drones can’t obviously compare to the bigger ones but yes I understand the money factor. Regarding the distance, well gps will always make some call on the resulting scale and transformation in space.