1. A method comprising: collecting a first digital object using a mobile device at a first time stamp; assigning a geographic location to the first digital object according to a current location of the mobile device; receiving familiarity score for the current geographic location, wherein the familiarity score is calculated based on a quantity of previously generated digital objects within a distance to the current geographic location; setting a time period based on the familiarity score; associating the first digital object with a second digital object generated within the time period to the first time stamp of the first digital object, calculating an adjusted familiarity score over time according to user activity; wherein the time period is set longer as the familiarity score indicates the mobile device is less familiar with the current geographic location of the mobile device; and decreasing the event time period in response to the adjusted familiarity score, wherein the associating for the first digital object and the second digital object is changed based on the adjusted familiarity score.