LA Sheriff's bizarre Compton surveillance

Matthew says:

For nine days in 2012, the Los Angeles County Sheriff used a spy plane to record low-resolution images of every corner of Compton. Residents of Compton were not told they were under aerial surveillance.

The LASD initially claimed Compton was chosen because the city is flat. Critics pointed out most of Los Angeles County is flat, and asked whether Beverly Hills would also undergo aerial surveillance.

Journalists also pointed out the videotaping:
1: Is too low-resoltuion to identify anyone, so…
2: it's worthless as evidence, and…
3: The video wasn't real-time so police wouldn't catch anyone in the act

So what, exactly, was the point of this expensive program?