The DSL promises that will be adding more maps to American Panorama. I can't wait to see the next ones!
The second atlas is called the Atlas of the Historical Geography of the United States. DSL took that atlas, which was originally published in 1932, and enhanced it with modern mapping functionality.
This atlas has 38 chapters. Clicking on any chapter (like Political Parties and Opinions, 1788-1930) takes you to a page to look at geographic and voting data on associated topics (like votes in Congress on the Maysville Road Bill, Compromise of 1850, and Dingley Tariff).
This video explains some of the features DSL built into the enhanced map.
DSL also created two engrossing videos that use maps to describe Richmond and its slave market in 1853 and the fall of Confederate Richmond in 1865.