Some call this viz – created by Charles Minard in 1869 – the best ever because it displays so many different kinds of information so clearly. Kim Rees of Information Aesthetics recreated this viz and used it as a measuring stick in her review of social visualization tools. We like the review and we love the viz. While not original, it has a certain je ne sais qua.
How’d they do that?
The key to the map is getting the movements of the troops right. This viz would be elementary if Napoleon had just marched his troops triumphantly to Moscow (you could just use longitude and latitude data). But as it happened, he also made a bloody and frozen retreat so if you don’t include a time sequence your viz will be a garbled mess (like this):
So the Viz has to account for time and the way Napoleon split up his troops. When we look at the underlying data, Kim has enough detail to tell the whole story:
In this case Kim simulates time with a Number dimension (num 1, 2, 3, etc.) placed in the Path field and adds the Group dimension (for separated armies) in the Level of Detail field. Giving us:
We’re starting to see something that wouldn’t make Minard roll over in his grave. Add direction (advance or retreat) to the color field and the rest of the map is just a labeling exercise.
On a side note, we came across a PowerPoint viz that might indeed make Minard roll over in his grave. Visualising data thoughtfully reviews this attempt by a leading consulting firm: