What to read (and watch) to understand data and visualisation

DESPITE THE relatively recent advent of data journalism and visualisation, the practice of analysing data is an old one. In 1786 William Playfair, a Scottish engineer and secret agent, invented the first bar chart. The Economist was founded in 1843 and printed its first one five years later. Around the same time, as cholera plagued London, a doctor called John Snow mapped cases of the deadly disease to find the common cause among his patients. He pinpointed a local water pump and therefore had its handle removed. That helped stop the epidemic.