Stacked graphs – geometry & aesthetics

Posted on 02/02/2011 by

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What goes into visualizing complex data?  Lee Byron and Martin Wattenberg, two prominent designers in their field, provide an interesting background in their explanation (or defense) of an (in)famous graphic.

In February 2008, The New York Times stirred up a debate. The famous newspaper is no stranger to controversy, but this time the issue was not political bias or anonymous sources—it was an unusual graph of movie ticket sales.

What made the graph so unusual?  See below (here for the original article):

Not that bad.

But nonetheless, people seemed to have strong reactions to seeing their consumption habits visually (their project initially visualized people’s last.fm listening preferences).  In their 2008 paper (link here), they explain that their visual reasoning originated in very concrete mathematical thought.

The main idea behind a stacked graph follows Tufte’s macro/micro principle: the twin goals are to show many individual time series, while also conveying their sum. Since the heights of the individual layers add up to the height of the overall graph, it is possible to satisfy both goals at once. At the same time, this involves certain trade-offs. There can be no spaces between the layers, since this would distort their sum. As a consequence of having no spaces between layers, changes in a middle layer will necessarily cause wiggles in all other surrounding layers, wiggles which have nothing to do with the underlying data of those affected time series

A designer by the name of Zach Beane then reimagined Byron’s work, emphasizing the run of the film (notice how Avatar, in orange at the top left, seems to snake on for a while):

(Its interactive.  Click here to see other films and years).

What I think is particularly cool about this is that it demonstrates how subtle differences in design can make substantive changes in the focus of the data.  While social scientists like myself would be inclined to run a new regression or shape the data in some way, these examples show how visual data can prove a point in a much more accessible, and ultimately novel, way.

Bertin, J. (1983) Semiology of Graphics (translated by A. Berg). University of Wisconsin Press.

Cleveland, W. (1993) Visualizing Information. Hobart Press.

Tufte, E. (1986) The Visual Display of Quantitative Information. Graphics Press.

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Posted in: Creative, Images