Abstract: The invention provides a data visulisation system comprising a data value memory in which is maintained an interaction database of interaction data representing interactions between customers and merchants, the interaction data associated with at least one time value, a retrieval device arranged to retrieve from the interaction database data representing interactions between customers and merchants and to construct a finite set of data values from their retrieved data, a display arranged to display a first representation of the data values, and a pointing device enabling a user to select part of the first representation. The display is further arranged to generate and display a second representation based on the part of the first representation selected by the user.