Redefinition of enumeration district centroids: a test of their accuracy by using Thiessen polygons

A method for estimating areal boundaries around centroids is by the generation of Thiessen polygons. In this paper the efficiency of such polygons as estimates of enumeration district (ED) areas is discussed. A new set of centroids and polygons is defined by use of Pinpoint Address Code (PAC) data and it is argued that these provide a more reliable estimate of 'true' ED areas than do OPCS (Office of Population Censuses and Surveys) centroids. More importantly though, the efficiency of these new centroids and polygons is demonstrated by using PAC data for individual buildings.