We selected D3.js for the library’s powerful features in building interactive, web-based visualizations. Given the numerous connections in the network, interactivity was important to drag the visualization and zoom into and out of concentrated portions. Different iterations of the network contained the following features:
- Labels for each person in the network
- Tooltips to display additional information from the underlying dataset
- Curved links between people to show the direction of the letters
- Variable widths for each link based on the number of letters sent
- Colors for each link based on the archive housing the underlying data
The below picture is a bird’s eye view of a simplified version of the network:
While building the visualization, I spent several hours with the underlying data listing the different ways the visualization could be customized. In doing this, I noted a couple challenges with the organization of the data. The first is the different types of senders and receivers of the letters. While most of them are individuals, some are couples, institutions, and different iterations of miscellaneous. The network, then, is not strictly person-to-person as it includes other types of senders and recipients. The second challenge is the dates attached to the correspondence. Each link includes the date range in which the letters were sent. For large volumes of letters sent between intellectuals in the network, it is unclear when most of the letters were sent. Having more precise dates would facilitate historical analysis about changing correspondence patterns during the Weimar Republic, the period for which most letters are dated.
In future, I plan to apply what I learned from the summer collaboration to my dissertation research. I have been thinking about ways to visualize the changing internal trade networks in West Africa. The challenge with this, though, is the paucity of consistent historical data on internal trade. Nonetheless, there are small pockets of robust historical information on the changing nature of the trade.