In a previous post I offered some thoughts on Haverford’s copy of De Revolutionibus and some initial information on where copies of De Rev had been, see: Editions of Copernicus’s De Revolutionibus. This post adds some further thoughts.
I updated the heat map to include when a copy of De Rev moved from one collection to another in the same city. Previously, I had only noted when the city had changed. Paris continues to have a large concentration of copies. London, Oxford, and Cambridge all now reflect a greater concentration. It seems that lots of copies moved from one library or collection to another within the same general area.
The full-size version is here:
Heat Map of Copernicus’s De Rev.
I was also interested in tracking the movement of copies of De Rev. There are lots of ways to represent this movement from place to place. The busiest but most fine grained would be city-to-city. Initially I thought I would do something like A Network Framework of Cultural History. That is, I liked the videos they created to show the movement of people from birth to death locations (I have reservations about the methods they used, but I liked the visual representation). But then I started thinking about other ways to represent movement. This chord diagram of global migration was really interesting: The Global Flow of People.
Guy Abel has done some great stuff with chord diagrams, much of it more sophisticated than I needed. Looking at the gallery of D3 examples revealed a bunch of great chord diagrams. Then I came across Steve Hall site. His two tutorials on building chord diagrams with D3 were great: Chord Diagrams in D3 and the update, Interactive Chord Diagrams in D3. He was generous enough to post the code to GitHub. Working through his tutorials and then modifying his code in really minor ways allowed me to produce this great chord diagram of showing how copies of Copernicus’s De Rev moved around the world.
A static chord diagram is fun and all, but an interactive one would be all the more interesting. Fortunately, Steve’s code provides that interactivity. So when you scroll over a country, you see where those copies went (within the country or to others). You can also point to the paths from country to country to see details about the flow of De Rev between countries.
If you want to see the interactive, full-size chord diagram, it’s here:
De Rev Chord Diagram.
A few quick notes:
- This diagram reflects only the copies that moved (either within a country or between countries).
- There’s a hiccup with the current data file that reports 0 copies in Japan, Hungary, Greece, and Canada (I’ll figure it out in the next iteration).
- The number of collections listed are not unique collections, e.g., the 140 collections in Germany are not 140 different collections, but rather 140 instances when a copy of De Rev was in a collection in Germany.