Crowd-sourced event identification that maintains source privacy

An automated method that generates crowd-sourced event notifications, the method comprising:

• retrieving sensor data at a plurality of mobile devices;
• detecting and processing, at each of the plurality of mobile devices, a plurality of events based on the retrieved sensor data;
• receiving, at an identity server, an identification message from each mobile device in the plurality of mobile devices, each identification message comprising key;
• receiving, at an analytics server, a notification message from each mobile device in the plurality of mobile devices, the notification message comprising processed sensor data for multiple events from the plurality of events, the notification message encrypted using the key associated with each mobile device;
• receiving, at the analytics server, the key from the identity server;
• decrypting, at the analytics server, the notification message using the key associated with each mobile device;
• generating, at the analytics server, a set of summary nodes based at least partly on the notification messages, wherein each summary node in the set of summary nodes is associated with multiple notification messages;
• associating each node in the set of summary nodes with a geographic location;
• generating a set of equally sized non-overlapping cells that span the geographic location;
• and
• subdividing any cell from the set of equally sized cells that includes a number of summary nodes that exceeds a specified threshold.