I visualize the flow of texts from one media form to another using SankeyMATIC.
Visualizing the relationships between authors, publishers, and periodicals in Pajek pointed me to areas that required further research.
Mapping places that have disappeared
I've been able to geolocate publishers' 19th-century offices at London addresses that no longer exist by using Harvard's Map Warper to geolocate contemporaneous maps and view them in GoogleEarth.
Mapping election results
Using R, I've produced series of maps to understand the electorate using election results at federal, provincial, and municipal elections.