Method and apparatus for generating sub-trajectories for a trajectory

An apparatus comprising at least one processor and at least one non-transitory memory including computer program code instructions, the computer program code instructions configured to, when executed, cause the apparatus to:

• retrieve, by the at least one processor from one or more sensors of a mobile device over a communications network, trajectory data comprising a plurality of data points defining a trajectory;
• iteratively execute, by the at least one processor, a set of operations until a termination condition is met, the set of operations comprising:
• selecting an observation point associated with one of the plurality of data points, and
• calculating a set of visible points comprising one or more data points from the plurality of data points, such that the set of visible points are associated with the observation point based on a predefined visibility context criterion;
• identify, by the at least one processor, a changing point from the plurality of data points based on the iterative execution of the set of operations until the termination condition is met;
• generate, by the at least one processor, an anonymized sub-trajectory for the trajectory such that the changing point indicates a starting point of the anonymized sub-trajectory;
• and
• output, by the least one processor, the anonymized sub-trajectory to at least one location-based service.

A non-transitory computer-readable storage medium having computer program code instructions stored therein, the computer program code instructions, when executed by at least one processor, cause the at least one processor to:

• retrieve, by the at least one processor from one or more sensors of a mobile device over a communications network, trajectory data comprising a plurality of data points defining a trajectory;
• iteratively execute, by the at least one processor, a set of operations until a termination condition is met, the set of operations comprising:
• selecting an observation point associated with one of the plurality of data points, and
• calculating a set of visible points comprising one or more data points from the plurality of data points, such that the set of visible points are associated with the observation point based on a predefined visibility context criterion;
• identify, by the at least one processor, a changing point from the plurality of data points based on the iterative execution of the set of operations until the termination condition is met;
• generate, by the at least one processor, an anonymized sub-trajectory for the trajectory such that the changing point indicates a starting point of the anonymized sub-trajectory;
• and
• output, by the least one processor, the anonymized sub-trajectory to at least one location-based service.