1. An apparatus for determining a path, the apparatus comprising: a first path module configured to receive, via a receiving device, a request from the individual for an initial patrol path to patrol within a road net, the road net comprising a plurality of nodes, the request including a start point of the individual within the road net; a path device configured to determine the initial patrol path using the start point, and transmit, via a transmitting device, the initial patrol path to the individual; a processor-implemented probability calculating module configured to calculate an event displacement probability within coverage of the initial path obtained by the first path module, wherein the event displacement probability is used to determine a likelihood of a relocation of an event from within the coverage of the initial patrol path to a location outside the coverage of the initial patrol path in the absence of the individual on patrol in the initial patrol path; and a second path module configured to change the initial patrol path to a modified patrol path based on the event displacement probability; wherein the transmitting device is further configured to transmit the modified patrol path to the individual.