Surveillance is in everybody's mind now with the advent of drones
Surveillance and specifically aerial surveillance via drones has become a big business. It is also very sensitive because it has many thought about their privacy. Privacy matters because people are being snooped at from up in the air and during their most private space. But we will have to look at the larger space because there are more than enough of benefits as surveillance from a remote point make a lot of thing possible.
There are several different methods of surveillance, including surveillance of a large track of agricultural land, via camera observation, home security via camera mounted drone, data mining and profiling, and biometric surveillance among others. There were a lot of limitations when using a land based camera system like it would be difficult to take a view from an impossible angle. Then there is the issue of discretion as the camera would not be able to go on stealth mode like when you mount it on a small drone.