Charles Minard was a pioneer of the use of graphics in engineering and statistics. Probably his most famous creation was a flow map showing Napoleon's disastrous Russian campaign of 1812. His map displayed:
- the army's location and direction, showing where units split off and rejoined
- the declining size of the army
- the freezing temperatures (by date) during the retreat
There used to be a good Google Maps based visualization of Minard's flow map, created by Mike Bostock. Unfortunately Minard's Naopleon has fallen fowl of Google's discontinuation of version 2 of the Google Maps API. Ironically the timeline temperature is all that survives now. However the code is still there if anyone wants to update it to work with version 3 of the Google Maps API.