Mapping swaths of history

I stumbled across this post http://www.wired.com/2014/10/ed-mccarthy-boston-history-mapper/ about Ed McCarthy who is mapping the entire history of Boston. What a job! Can you imagine deciding what belongs on a map? Finding the map and then determining how to document it, connecting event to map? If this was for my class, we'd have to do some serious brainstorming about types of events, types of maps, display, "collection development", access points, indexing, and so much more. Take a look at the article. How would you approach mapping and documenting your community?