1. A method implemented at least partially by a processor, the method comprising: creating a location-activity matrix by detecting stay points to represent a set of stay regions representing stay points where a device associated with an individual has stayed over a time threshold within a distance threshold, and by extracting user comments from global positioning system (GPS) logs of the device corresponding to the set of stay regions; creating a location-feature matrix by identifying points of interest (POI) in a region and determining a number of different POI in an enclosing polygon of stay points; creating an activity-activity matrix by identifying a correlation between a pair of activities; and associating information from the location-feature matrix and the activity-activity matrix with the location-activity matrix.