Videos to help you get started with R: these will walk you through sections 2.2 - 2.6 of Humanities Data in R, showing you how to work with R in the command line (Part 1), RStudio console (Part 2a), R scripts (Parts 2b and 3), and R Markdown notebooks (Parts 4a, 4b, and 4c).
Susan Schulten, 2012, Slavery and the Origin of Statistical Cartography, pp. 119-155 in Mapping the Nation: History and Cartography in Nineteenth-Century America (Chicago: University of Chicago Press).
Scott Nesbit, 2014, Visualizing Emancipation: Mapping the End of Slavery in the American Civil War, pp. 427-434 in Justyna Zander and Pieter J. Mosterman, eds., Computation for Humanity: Information Technology to Advance Society (New York: CRC Press).