Public access to conversion of data between geographies, with multiple look up tables derived from a postal directory

Comprehensive statistical analysis of local areas and variation between them demands that data held for a variety of geographical source units are made compatible. Geography conversion tables enable transfer of data from one set of geographical units to another, but have in the past been generated for specific projects, while their use has required database programming skills. The derivation of multiple geography conversion tables for public use is specified from the UK-wide 'All-Fields Postcode Directory' (AFPD). The results are validated using alternative constructions including geographical information systems. The accuracy of conversion tables is measured. Access is achieved through list-matching algorithms and a World Wide Web interface http://convert.mimas.ac.uk, which allows the public user to convert their own data between postal, electoral, census, administrative and statistical geographical boundaries. The data conversion is improved by proportional allocation for those source units that do not fit within a single target unit. The architecture of the site allows further tables from any source to be incorporated. The current demand for computational geography to meet small area statistical requirements leads to a discussion of priorities for the improvement and maintenance of geography conversion tables. © 2002 Elsevier Science Ltd. All rights reserved.