Don’t forget the drones and the Hi-Res satellite shots. Googleearth, anyone?
It has a great view of my garden, as well as what that space looked like a couple of years before it was started. High enough resolution that I can even see the fence lines & posts, the individual wires of the power lines, and the rototiller parked. Same for the new roof on the house, and other improvements & changes to the property, such as brush clearing.
Truth is, such activities are not able to be hidden, as there are even higher resolution "earth resources" satellites that can even identify which types of crops are growing, and somewhat of their condition/stress levels.