How do you make sense of hundreds of years of handwritten scholarly correspondence? Humanists at Stanford University had the same question, and developed the project Mapping the Republic of Letters to answer it. The project maps scholarly social networks in a time when exchanging ideas meant waiting months for a letter to arrive from across the Atlantic, not mere seconds for a tweet to show up in your feed. The tools used in this project inspired the Humanities + Design lab at Stanford University to create a set of free tools specifically designed for historical data, which can be multi-dimensional and not suitable for analysis with statistical software. Enter Palladio!

To start mapping connections in Palladio, you first need some structured, tabular data. An Excel spreadsheet in CSV format with data that is categorized and sorted is sufficient. Once you have your data, just upload it and get analyzing. Palladio likes data about two types of things: people and places. The sample data Palladio provides is information about influential people who visited or were otherwise connected with the itty bitty country of Monaco. Read on for some cool things you can do with historical data.

## Mapping

Use the Map feature to mark coordinates and connections between them. Using the sample data that HD Lab provided, I created the map below, which shows birthplaces and arrival points. Hovering over the connection shows you the direction of the move. By default, you can change the map itself to be standard maps like satellite or terrain, or even just land masses with no human-created geography, like roads or place names.

But, what if you want to combine this new-fangled spatial analysis with something actually historic? You’re in luck! Palladio allows you to use other maps as bases, provided that the map has been georeferenced (assigned coordinates based on locations represented on the image). The New York Public Library’s Map Warper is a collection of some georeferenced maps. Now you can show movement on a map that’s actually from the time period you’re studying!

## Network Graphs

Perhaps the connections you want to see don’t make sense to be on a map, like those between people. This is where the Graph feature comes in. Graph allows you to create network visualizations based on different facets of your data. In general, network graphs display relationships between entities, and work best if all your nodes (dots) are the same type of information. They are especially useful to show connections between people, but our sample data doesn’t have that information. Instead, we can visualize our peoples’ occupation by gender.

The network graph makes it especially visible that there are some slight inconsistencies in the data; at least one person has “Aristocracy” as an occupation, while others have “Aristocrat.” Cleaning and standardizing your data is key! That sounds like a job for…OpenRefine!

## Timelines

All of the tools in Palladio have the same Timeline functionality. This basically allows you to filter the data used in your visualization by a date, whether that’s birthdate, date of death, publication date, or whatever timey wimey stuff you have in your dataset. Other types of data can be filtered using the Facet function, right next to the Timeline. Play around with filtering, and watch your visualization change.

Try Palladio today! If you need more direction, check out this step-by-step tutorial by Miriam Posner. The tutorial is a few years old so the interface has changed slightly, so don’t panic if the buttons look different!