About the Data

This project uses version 4.1 of the “Formal Alliances” dataset available through the Correlates of War project [1]. The “Formal Alliances” dataset includes time series data on different types of alliances between members of the interstate system, covering a period from 1816 to 2012. We also used Google's developer country dataset for country coordinates.

To preprocess the data, we had to first link the Google country coordinates to the dataset country IDs, a process we wrote a Python script to accomplish. We also had to convert the data into nodes and links in order for the data to be usable in our visualizations, which we also accomplished through a Python script. Lastly, due to the changing landscape of the world over time, we had to manually make some changes for countries that no longer exist or ones that were established recently.

The types of alliances represented in the dataset include:

• Defense: one or more members of the alliance has committed to defend other members of the alliance.
• Neutrality: alliance terms include a promise to remain neutral in conflicts involving other members of the alliance
• Nonaggression: alliance terms include a promise not to attack one or more states in the alliance
• Entente: an informal alliance; an understanding that the state would consult with one or more states in the alliance if a crisis occurred

Countries that do not exist today (for instance, Yugoslavia) are not shown on the map. Thus the "Network" view may be particularly useful for the 50 or so years of data, as it displays alliances between the pre-unification German and Italian states.

[1] Gibler, Douglas M. 2009. International Military Alliances, 1648-2008. CQ Press.