Data visualization and storytelling


A visual exploration of a 15th century bookshop

A collaborative project with the University of Oxford

Step back in time and join us on a visual exploration of a 15th century bookshop. Recently, we collaborated with Cristina Dondi, a Professor of Early European Book Heritage at the University of Oxford, on her research of the prices of books sold in Venice in the late 15th century. Through a unique manuscript ledger of a Venetian bookseller, we were able to uncover insights on the most popular titles, the fastest selling books, and the origins of the books sold. Join us as we delve into the past and uncover the secrets of this 15th century bookshop through the magic of data visualization.

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The ledger — a book of accounts — is a rare record from this period and a window to the past. It contains detailed information on the books sold by Francisco di Madiis between 1484 and 1488, like book title, author, genre, printing place, name of the printer, price, number of copies sold, date of printing, and date of sale.

Together with Professor Neil Harris from the University of Udine, Professor Dondi transcribed the data of 700 editions identified in the ledger — a total of over 13,000 printed books sold — into a spreadsheet. At Flourish, we helped them share the insights of this data in a clear and more appealing way through visual storytelling.

Here are some highlights from the project, which was presented in the Sandars lectures in bibliography at Cambridge University.

Finding the bestsellers

One quick way to spot the most popular books was to visualize the titles with most copies sold, as we did in the bar chart above. Then, we colored the bars by subject to split them into groups. You can toggle between these two versions by clicking on the arrows in the story.

However, Professor Dondi was also interested in showing how quickly books sold, another marker to determine their popularity. For this, the beeswarm mode on our Scatter template was ideal, as we positioned all the records along an axis representing time to see which sold first.

In this chart, the axis represents the number of days between the printing date of a book and its sale. Hover over each dot to get more information about each specific book, or use the dropdown filter in the chart to see how books in each subject sold over time.

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When we sized the dots based on the total number of copies sold for each book, we could identify the books that sold quickly and in big quantities overall: the bestsellers. To achieve this, we used our premium Data Explorer template.

The bubbles are colored by subject. Literature, Law, Liturgy, Grammar and Theology were the most common ones by number of copies.

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Where did the books come from?

Another focus point in the project was the printing location of the books sold. Unsurprisingly, most editions were printed in Venice where the bookshop was located. We removed these records from the chart since we wanted to focus on the origin of imported books. As a result, we identified other printing hubs at the time in the rest of Italy and other European cities.

This arc map shows the flow of the books from their printing location to their final destination in Venice. The thickness of the line represents the number of copies printed in each place.

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As you can see, most books came from different regions in Italy, but this map also highlights France, Switzerland and Germany as other popular printing sites. As Professor Dondi said: “The map may be simple but the evidence is historically very valuable, and presenting it in this visual format makes the exposure of the data more powerful.”

Using charts as research tools

Professor Dondi said that one of her favorite charts from the project was the sankey diagram showing the relationship between the printing place and the subject of the book in the dataset. This chart helps us understand the volume of work produced on each location. With it, we can identify whether a specific genre was mostly printed in a certain location.

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For Professor Dondi, this chart meant that she could better understand the production of the places outside of Venice, as she could interact with the chart and focus on a specific location by clicking on a single node. The chart works as a showcase tool and an exploratory one.

Big picture versus granularity

One of the biggest challenges while working on this project was to strike a balance between showing overarching trends in the data versus specific details. Some topics called for charts that focused on a broader perspective, while others needed a more close-up look. This is why understanding when to use which chart is crucial.

The variety of chart types and approaches helped tell Professor Dondi’s story more clearly: “They did justice to the exceptional granularity of my data. They produced the big picture, as well as the detail”, she said.

To learn more about Professor Dondi’s research project, visit the Printing Revolution website.

How to make a project your own

Aesthetics play a big role in data visualization and this was especially true in this project. The charts were brought together by their cohesive theme and color palette, all possible thanks to Flourish’s options to customize charts. Read our previous blog to learn how to quickly enhance your charts with some simple tricks.

Need help creating a special project or chart? Take a look at the Flourish Experts Network where you will find a series of designers, developers and agencies to connect with.