I'm happy to share two further iterations of my recent slavery mapping.
First, a collaboration with Matt Daniels (of Polygraph fame) on the historical-geographic relationship between slavery and mass incarceration. Besides showing a remarkable overlap between the two (especially for prisons, but also for short-term jails), this was also an opportunity to put my new bubble-grid mapping technique to good use in an interactive narrative. Because the bubble grid doesn't rely on jurisdictional shapes, it's great for comparing data over very long time spans (200+ years) and for showing urban and rural population at the same time. This project is the second installment of The Pudding, a series of weekly visual essays for 2017. ("The proof of the pudding...")
Second, Michael Ralph and I have published an expansion of our slave-insurance map in the January issue of Foreign Policy. The size of our database increased from about 700 policies (in version 1) to over 1300 policies; the new policies are mostly from the archives of Baltimore Life. The overall pattern is similar — steamboats on the Ohio River, coal mines in Virginia, and skilled labor in Atlantic port cities — but the new data also includes more industrial occupations and information about slave values and premiums.