Well, Minard's graphic is actually 2 charts - the top one maps distance/abstract geography (2 dimensions), size of the army, and time/direction of movement. The

Well, Minard's graphic is actually 2 charts - the top one maps distance/abstract geography (2 dimensions), size of the army, and time/direction of movement. The bottom one maps the temperature to time during Napolean's retreat. It's tough to encode more than 3 separate dimensions on a chart (usually 2 spatial axes and a color/shape/size axis) and have it still be useful for analysis/presentation.