Tom H. C. Anderson - Next Gen Market Research

1870 Statistical Atlas of the Ninth Census

After all the interest in yesterdays post about the census I did a bit of googling and found a copy of the 9th census online. Antiquated race terminology aside, I’ve got to say, the data visualization is quite impressive especially when you consider they are 140 years old! Heat maps and tree maps are still very popular forms of info graphics today.

Tree mapping is sometimes used to display hierarchical data. We’ve used them with text analytics in some cases, nesting rectangles to represent different levels of data. However in the 9th Census this does not seem to be the primary reason for their use. Rather perhaps one reason for their use here is to make efficient use of space while showing several variables.

Still I wondered, why such prominent use of tree maps. The bar, stacked bar and pie charts we are so used to seeing today are there but not in color. I thought tree mapping was a more recent data visualization tool as it requires the use of a tilting algorithm and is difficult to order.

Perhaps, and this is just a guess, but in 1870 a large part of the population was obviously involved in agriculture. As land owners and farmers they would have been used to looking at large maps depicting rectangular land parcels. They would probably also be used to allocating various smaller rectangular parcels within their own parcels for property leases/renting and of course for planning which combination of crops to grow and in which proportions.

So in 1870 these maps may have communicated more effectively to the target audience than any pie or bar chart?

Fascinating that they were using the same data visualization techniques which are so popular today. We could probably take a lesson in terms of knowing our audience better, assuming that’s why tree maps were used. If anyone knows more about the history of tree, pie, bar charting etc. would love to hear your thoughts.

If you’d like to see the entire 9th census atlas in high resolution you can download it via the link below.

http://www.radicalcartography.net/index.html?9thcensus

@TomHCAnderson