One of the central challenges in investigating population data over a span of time arises from the shift that inevitably take place as the system of collection (e.g. the census scheme) or the administrative units themselves evolve. Without tracking these changes, comparison of data from different years is impossible.
 
 
In 2008, I began looking for GIS shp files suitable to use for managing Irish historical data from the nineteenth century. One of the stellar models for this type of work is the University of Portsmouth's Great Britain Historical Geographical Information System and its user-friendly companion site A Vision of Britain Through Time . . .