President Lincoln’s Data Driven Decision Making


1860 Census Slavery Map

The screenshot above is from my Tableau replica of an original map, which you can find here, that was presented to President Lincoln in 1861 to show the prevalence of slavery in the American South. This viz first caught my eye during Michael Sandberg’s presentation at the Fringe Fest. I was taken aback by the fact that even in year 1861, humans wanted to see data in a well designed visual manner that was easily digestible and strong in its messaging. I was searching for my next Tableau Public project and after listening to Mike Cisneros’s talk at The Fringe Festival about how we are all artists our vizzes have the power to influence others, I immediately got to work. 

After contemplating upon whether or not I wanted to do a replica or a remix of the historical viz, I decided that a close replica would be both a good exercise and a powerful viz. I started by understanding the message and metrics embedded in the viz. The county’s in Lincoln’s original were county’s from the 1860 census, so shapefiles containing current day counties would not do. Each county was colored by the percentage of residents who were enslaved based on the 1860 Census data. After many Google searches and blog views I realized that Social Explorer is one of the best sources for Census data available. The Census data from Social Explorer, combined with historical shapefiles of Census county areas (The Newberry Library) provided me with all the data need to replicate this viz. Since the Census data was so old, there were some oddities in the way the data was reported, such as South Carolina utilizing three reporting area methods (county, district, parish) that overlapped throughout the state. Some manual manipulation in Excel was required to clean the final data set. 

This viz is actually made up of only two worksheets in Tableau, the main map and the data table. I used Powerpoint and UglyQua font to recreate the text found inside the original, and then Cambria (italics) in the data table. I used Tableau’s ‘pick screen color’ option to match the background and the shading colors so that they were as close to the original as possible. The original viz had county name and percentage enslaved peoples labeled on the map, but the smallest I could get the Tableau labels to go was a 6 font, so I had to settle for just some of the percentages being displayed. 

During the creation of this viz I was truly humbled to think that our nation’s Presidnt used this same information 150 years ago to inform his decisions that decided the fate of a nation. This viz particularly contradicted the notion that the South’s decision to secede was due to “state’s rights.” The argument goes that the Southern states were more in favor of state’s ability to govern themselves free of federal government involvement. Due to the issue of slavery, federal involvement was inevitable, and the South didn’t want any part of it. And why would they? The economic and social wealth that whites were accumulating in that region and time period was immense. To oppose slavery was to oppose one’s own wealth and social privilege. In an effort to spin the true reason for the South’s succession away from the enslavement of African Americans, the “state’s rights” argument emerged. In reality, “states rights” was code for trying to preserve slavery which would then preserve the wealth being generated from this system of unpaid labor and oppression. 

The viz that I have recreated showed the expanse of the enslaved person’s market and their effect on the South’s economy. This Slate article says that, “President Lincoln referred to this particular map often, using it to understand how the progress of emancipation might affect Union troops on the ground.” The impact that this viz had on the President’s understanding of the world undoubtedly had an effect on his thoughts and actions pertaining to slavery and its centrality to the Southern cause.

As data analysts, we cannot forget how powerful our visualizations and analyses can be. Be an artist, be powerful, and make your viz leave an impact on its audience. Thanks for reading my blog post. Make sure to email me with any thoughts or comments! 

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