Up in the Air: Applying the Jacobs Crowd Formula to Drone Imagery

The accurate estimation of event size is important for city planners, concert coordinators, social movements and anyone else interested in understanding how many people show up to an event. For social movements, the social theorists Charles Tilly long ago argued, large crowds signal worthiness, unity, numbers and commitment. Huge crowds on the street are a clear signal to authorities, the media, bystanders and the media itself. The same can be said for events with small turnouts. Event coordinators often have interests that lead to methods that inflate estimates. Critics and movement targets, on the other hand, are interested in minimizing the perceived size and scope of protests to their authority. Current efforts to estimate protest size have used on-the-ground methods (requiring many enumerators total control of the event area) or in-the-air methods (such as traditional aircraft, which are expensive and require advance notice and special permissions). Technological innovation involving Unmanned Aerial Vehicles (or “drones”) provide an opportunity tomore accurately and affordably estimate crowd size. In this brief methods article we introduce a novel adaptation of a standard estimation model (Jacobs Crowd Formula) for use on an entirely new platform.