On the spatial representation and accuracy of address-based data in the United Kingdom

Abstract A major task in applications of geographical information systems is to translate from address codes to grid references. In the United Kingdom this is commonly accomplished using the Central Postcode Directory (CPD), which allows conversion of postcodes to Ordnance Survey grid references. A commercial company, Pinpoint Analysis Ltd, is currently digitizing all properties and attaching postcodes. The paper assesses the accuracy of CPD data compared with Pinpoint data, especially in terms of how the grid references in the two cases relate to the boundaries of enumeration districts (EDs). Results from a small-scale study in Cumbria suggest that nearly 40 per cent of postcodes from the CPD file may be misallocated to EDs.