• geographical information systems;
  • monitoring;
  • postcode;
  • spatial concentrations;
  • target geography;
  • Amsterdam

Public agencies typically collect statistical databases on population, housing, economic activities and various other indicators. In their existing form, these databases cannot be directly adopted for planning and policy formulation, as they need to be tailored to the issue for which information is required. The specific problem addressed in this article is how to process and visualise small-area data, in our case referring to the Dutch 6-digit postcode, to provide detailed information for areas that are normally difficult to target in policy terms because they do not relate to the identifiable administrative entities that planners and politicians are accustomed to. Therefore a methodology is presented that identifies spatial concentrations based on the underlying data using geographical information systems (GIS). Emphasis is placed on the technical characteristics of this method, which has been applied in a number of urban studies, and on the advantages and disadvantages for further utilisation. Using the Amsterdam City Monitor as a case study, this paper illustrates how to produce detailed maps of urban dynamics within a city to support local policy and planning. It also shows that the presented method of mapping spatial concentrations can be applied to a variety of urban issues, and complements the common practice of using intensity classes to compare places.