You might simply describe it as an elaborate chart. This infographic of the American Civil War is making the rounds today on various social media channels. It dates to 1897, though the directions on how to properly interpret the chart have not survived. Apparently, a wave of these infographics was produced at the end of the nineteenth century and I am sure that it fits into an interesting cultural history of visual representations of large periods of time. Unfortunately, I don’t know anything about it, though I do see a loose connection with a Rankean optimism about the knowability of history.
You can click on the pic above for a high resolution image or you can play around with the zoom button at the Library of Congress. Enjoy and let me know if you figure out how to interpret it.