“When a graph is made, quantitative and categorical information is encoded by a display method. Then the information is visually decoded. This visual perception is a vital link. No matter how clever the choice of the information, and no matter how technologically impressive the encoding, a visualization fails if the decoding fails. Some display methods lead to efficient, accurate decoding, and others lead to inefficient, inaccurate decoding. It is only through scientific study of visual perception that informed judgments can be made about display methods. The display methods of Elements rest on a foundation of scientific enquiry.”

From the preface of William S. Cleveland’s
“The Elements of Graphing Data” [Cleveland 1989]

[Cleveland 1989] William S. Cleveland, The elements of graphing data, 10.[print.] ed. Monterey, Cal: Wadsworth, 1989, ISBN: 978-0-534-03729-1.

[Cleveland 1993] William S. Cleveland, Visualizing data. Murray Hill, N.J. : [Summit, N.J: At&T Bell Laboratories ; Published by Hobart Press, 1993, ISBN: 978-0-9634884-0-4.

The R code for the figure is the book and the data tables previously could be found from http://www.stat.purdue.edu/~wsc/visualizing.html. Some of this data and code can be found at https://github.com/rseiter/ClevelandDataVis and http://deltarho.org/.

Transcript

Now, William S. Cleveland's book, "The Elements of Graphing data", has a preface in it. Where he really talks about the fact that when you make a graph, you're taking the qualitative and categorical information and your including it using the display method, then he says, the processes of course now the viewer is going to look at it, and they're going to visually decode it, and he emphasizes how that's the very very vital link. So no matter how impressive the technology for the encoding, in the end, the user needs to be able to efficiently and accurately decode what it is that you presented. And in his book, he goes on to display that there are some fundamental elements to how to encode the data to facilitate the use of being able to decode it.