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Interactive Visualization: Correspondents in Voltaire’s Network

Dan Edelstein , August 2016

The data visualizations below were created using the Palladio application developed at Stanford. The embedded visualizations are Palladio Bricks. Palladio is freely available to use at and the source code is available on GitHub here.

You will find an explanation of the visualization at the bottom of the page.


#Voltaire’s Correspondence Network

There are four visualization elements to be found on this page:

  1. On top, visitors will find a map of Voltaire’s correspondents. Unlike the map of his correspondence, the points represented here are not sized according to the number of letters sent to or from a location, but by the number of correspondents in one place. Location metadata for Voltaire’s correspondence is incomplete, so We were only able to map letters with location metadata, meaning that close to 7,000 letters (or a little over one third) do not feature on this map at all. The map is interactive: hovering with the mouse over a point will reveal the number of letters to and from that place; hovering over a line will reveal the number of letters from one place to another. (NB: remember that these numbers only reflect letters with location metadata). All the metadata for Voltaire comes from the Electronic Enlightenment Project at Oxford University (subscription required). The visualization elements were produced using Palladio, a suite of data visualization tools created at Stanford University.

  2. Below the map is a histogram, which can also be used to filter the chronological boundaries of the map. Every year is represented as a bar, with the y axis indicating the number of letters sent per year. Since the temporal metadata is almost entirely complete, all of the extant letters in Voltaire’s correspondence are represented here. Each bar is also categorized by the nationality of sender or recipient (in other words, whomever Voltaire was writing to, or receiving a letter from). Hovering over the different sections of the bar will illuminate all letters by that nationality.

  3. Below the histogram is a faceted filter viewer. This viewer allows you to filter both the histogram and the map according to one or multiple values across one or multiple dimensions. For instance, by selecting “English,” “Scottish,” “Irish,” and “Welsh,” you can identify all of Voltaire’s British correspondents; or you can select “German” and “female” to identify the 16 German women with whom Voltaire corresponded.

  4. The names and letters associated with any group of individuals selected in this way appear below the histogram, in a table. The hot links on the left-hand side will take you to the Electronic Enlightenment page containing a transcription of this particular letter.

See the project Schema page for data viewer, the data schema, and a link to the data files.

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Cite as

Dan Edelstein. Interactive Visualization for Voltaire’s Correspondence Network. Correspondents in Voltaire’s Network [Created using Palladio,].