1. A method for providing an overview of a plurality of contexts of a target environment, the method comprising: receiving event data representing a plurality of events in the plurality of contexts over a monitoring period; displaying a schematic representation of the event data over the monitoring period using only a portion of the event data, the schematic representation being indicative of an activity density of the event data over the monitoring period; displaying, together with the schematic representation, a detailed graphical representation of the event data over a specified portion of the monitoring period using the event data for the specified portion of the monitoring period; receiving from a user, a selection generating a marker associated with an item of the schematic representation, wherein the displaying the schematic representation includes displaying said marker in the schematic representation, and wherein the displaying the detailed graphical representation includes displaying an indication of the marker in the detailed graphic representation; and wherein the displaying of the schematic representation includes displaying an event intensity graph including a plurality of graphical elements, each graphical element being indicative of an event intensity of one of the plurality of contexts.