An Online Census Atlas for everyone

Abstract

Central to the development of the online Atlas was the extraction of statistics that were comparable over the last four UK censuses and this process was facilitated by the use of the web-based resource, Linking Censuses through Time (LCT) (Dorling et al. 2001; Martin et al. 2002; Mitchell et al. 2002). The LCT project linked 1971, 1981 and 1991 census data at a number of geographical levels via a web-based interface, with the aim of facilitating change-over-time analysis. The census data were restricted to the countries of Great Britain; Northern Ireland data were unavailable to the academic com munity then. The resource was completed in 2001 and built on work previously carried out by Atkins et al. (1993) and Dorling and Atkins (1995) in which the 1991 census data were linked to the 1981 ward geography via look-up tables. 1971 cen sus data had also previously been aggregated to 1981 wards by Dorling (1991). As 1981 was the midpoint of the three census periods it was chosen as the geographical base for the resource. Access to the LCT data is via interactive menus to select options of date, geography and subject which are converted by the program into a Unix line com mand. This command line, which specifies which data are to be extracted from the compressed ver sions of the census data tables, is passed to existing C code which, in turn, reads external look-up tables to produce run-time aggregations to the requested geography. Output of the data is in CSV format. The end result of this project was streamlined access to census data from 1971 to 1991 across a wide range of geographical areas, including 2001 geographies such as parliamentary constituencies and local authorities (Martin et al. 2002). However, to continue serving social scientists needing infor mation on the change in social and spatial distribu tion of the population there was a need to incorporate 2001 census data. Although 2001 data are not cur rently available in the LCT resource, it does include 2001 geographies making it possible to extract cen sus counts from public-domain census tables pub lished by the statistical offices of the United Kingdom and merge the data with LCT data with relatively minor manipulation.