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Book review: The Functional Art

Cairo_book_coverReading Alberto Cairo’s fabulous book, The Functional Art, feels like reading my own work. It’s staggering how closely aligned our sensibilities are, notwithstanding our disparate backgrounds, he a data journlist by training, and I a statistician. We probably can finish each other’s sentences—and did at this recent Analytically Speaking webcast (link to clip).

Cairo currently teaches data visualization at the University of Miami; this is after a distinguished career as a data/visual journalist, having won many awards.

The Functional Art is divided into halves, which can be read independently.

The front part is a terrific overview of data visualization concepts. Cairo’s interest is in principles, rather than recipes. The field of data visualization has developed separately under three academic disciplines: design, computer science, and statistics. Inevitably, the work products contain contradictions and much re-invention. Cairo achieves a synthesis of these schools of thought, and this book is the clarion call for more work on unifying the key intellectual threads of the field.

The second half contains a series of interviews with industry luminaries. This section is a unique contribution to the literature, glancing at behind-the-scenes of the craft. Practitioners will find these short pieces illuminating and profitable. It is often a long journey to arrive at the graphic in print. The selection of designers emphasizes mainstream media outlets although the interviewees have wide-ranging views.

Included in these pages are plenty of published data graphics, frequently work that Cairo produced while working for the Brazilian publication, Epoca. These graphics are elaborate and ambitious, and nicely reproduced in color images. They reward detailed study, with attention to composition, narrative structure, chart types, selection of statistics, etc.

There are plenty of books on the market about how to do graphics (Dona Wong, Naomi Robbins, Nathan Yau come to mind.) Cairo’s book is not about doing, but about thinking about charts. Trust me, time spent thinking about charts will make your charts much improved.


I will now describe some sections of the book that particularly hold my interest:

In Chapter 3, Cairo explains the “visualization wheel,” a nice way to visualize the decisions that designers make when creating charts. Each decision is presented as a trade-off between two extremes. For example, a chart can be “light” or “dense.” This axis evokes Tufte’s data-ink ratio. Devices such as this wheel are useful for integrating the diverse viewpoints that coexist in our field. Frequently, these trade-off decisions are made implicitly—but they can really benefit from explicit consideration.

Figure 4.11 is one of the Epoca charts narrating a Brazilian election. Just recently, I linked to Cairo’s blog post about a similar chart. In both, a spider (radar) plot features prominently. On the same chart, you’ll find a nice demonstration of the small-multiples principle. I applaud the publisher of Epoca for supporting such deep data graphics.

Chapter 8 is invaluable in documenting the chart-making process. Trial and error is a key element of this process. Here, Cairo shows some of the earlier drafts of projects that eventually went to publication. This material is similar to what Kevin Quealy shows at his ChartNThings blog about New York Times graphics.

Chapter 9 is one of the more mature discussions of interactive graphics I have seen. Too often, interactivity is reduced to a feature that is layered onto any dataset. It should rightfully be seen as a problem of design.

Figure 10.1 is not strictly speaking a “data” graphic but I love John Grimwade’s visual explanation of the “transatlantic superhighway”.

Cairo also writes a blog.


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