π-Flow: Flow & charts for the study of population movement

π-Flow is a series of pieces of demonstration software for the visualisation of characteristics of human population dynamics which are widely studied in both economics and social science. Our visualisations are based on a 1% sample of the 2002 census in the USA. The modern census includes one aspect of historical data and it is this data namely, “Which county did you live in 5 years ago”, that we use to study population flow through the use of the adapted MapFlow algorithm in π-Flow. In addition we present an attractive/repulsive visualisation that shows an aggreate view of net popultion gain and loss. Finally, we present an established symbolic technique based on a pie-chart per state based visualisation that aids in the study of the ethnic breakdown across the lower 48 United States.