Sankey diagrams are great for visualising flows from one set of data values to another. Although named after Irish Captain Matthew Henry Phineas Riall Sankey, who used this type of diagram in 1898 to show the energy efficiency of a steam engine, the best know Sankey diagram is probably Charles Minard’s Map of Napoleon’s Russian Campaign of 1812, which he actually produced in 1869.
Thomas Rahlf: Datendesign mit R The above example from Thomas Rahlf’s book Datendesign mit R shows that Minard’s plot can be reproduced with base graphics in R.