I spent a lot of police flying time doing surveillance ops. Up at 3000' to 6000', dodging RPT under radar guidance, puttering along at 40-50kt, with an observer on gyro-stabilised binos watching a car from the left back seat, calling out left and right turns, cross-streets etc. Another observer in left front with a UBD street directory, calling out the names of the streets on the discrete frequency, plus other info like passing a red truck, passing the Mobil petrol station and so on, to the ground crews following further back. Often I would be in lazy progressive circles to keep the car at the optimum spot for the observer.
These days there are stabilised video and IR cameras, screens displaying gps info on street maps, the ability to lock onto a moving object without continually fiddling with the cross-hairs, a massive improvement on the 80s.
And a lot of this could be done by a drone, with no noise to give away our presence, almost impossible to see from the ground, cheaper to operate than a chopper with 3 people. But some dispensations would be needed to allow out-of-visual-range ops in controlled airspace and such.