Area chart in the context of William Playfair

William Playfair (22 September 1759 – 11 February 1823) was a Scottish engineer and political economist. The founder of graphical methods of statistics, Playfair invented several types of diagrams: in 1786 he introduced the line, area and bar chart of economic data, and in 1801 he published what were likely the first pie chart and circle graph, used to show part-whole relations. Playfair has been reported to have been a secret agent for the British Government, although this has sometimes been a subject of controversy.