1. In a data visualization system, a method of analysing and representing spatial data sets to optimize the arrangement of spatial elements which the data sets relate to, the method including the steps of: retrieving data associated with the data sets from a data storage module that is in communication with the data visualization system, determining lift values for a plurality of predefined spatial areas from the retrieved data based on a set of fuzzy association rules applied to the predefined spatial areas, determining spatial performance values for the predefined spatial areas, and combining the determined lift values and spatial performance values to show the relationship between each of the spatial elements within the predefined spatial areas.