Mapping the Battle of Bunker Hill

With the sestercentennial of June 1768 passing by, I have few days to devote to the Battle of Bunker Hill. But here’s Charles E. Frye’s map of that battle, completed in 2011 and available through Wikipedia. It’s unusual in positioning American army units on the Charlestown peninsula.

Frye is an army-trained cartographer. In this interview, Frye talked about how he came to make that map:

My wife suggested I help my oldest son with his 5th grade history project and that we could research to find out where [our ancestor] Isaac [Frye] was on the battlefield. Reading about the battle proved bewildering and disorienting. Therefore, my natural inclination was to make a map along with a timeline to organize that information. We started by mapping the Boston vicinity, including what was then known as the Charlestown Peninsula. Based on that and the major landmarks of the peninsula, we could then see the form of the battle and the sequence of events. My son hand-drew a one-page color map of the battle and wrote a short essay describing where Isaac most likely was located. We had narrowed it down to two possible locations. It took years before I finally located the documentation indicating which of the two was correct.

I ended up making my own map using GIS and because I learned the Library of Congress’s map division had copies of most of the maps depicting the battle, and already had a map-scanning program. GIS allows for scanned maps to be positioned relative to modern geographic data, which then could be used to create a historical map in the GIS. I knew a cartographer working at the Library of Congress, so I contacted her, and their staff bumped up the remaining maps of the battle so I could have faster access.

My map looked good to me, and it was rich with information. I shared it with the map division staff, and they liked it and cataloged a copy. However, the “Aha!” moment occurred for me two years later when I first visited the Bunker Hill Monument. There is a diorama there depicting the battle. Other than placement of the cannon, my map completely agreed with the diorama! How does a non-historian do that part-time in only a matter of months? With GIS of course. Mapping information in GIS forces rigor, which among other things affords efficiency because non-conforming information cannot be forced into database like it can be forced into a paragraph. I later published a data model and method for historians to use GIS in their work. I am happy to say many historians have since adopted, adapted, and expanded on that work.

Here’s more on Frye’s data model and method for others to use with G.I.S. systems.