Visualization literacy

Information visualizations can be read on two levels. First, the information they present; their intended meaning. Second, the visualization parameters: simplifications, conventions, assumptions, and lies used for expediency of presentation and background of the producer.

"The world is complex, dynamic, multidimensional; the paper is static, flat. How are we go represent the rich visual world of experience and measurement on mere flatland? (Introduction)

"Escaping this flatland is the essential task of envisioning information--for all the interesting worlds (physical, biological, imaginary, human) that we seek to understand are inevitable and happily multivariate in nature. Not flatlands (page 12)."

- Edward Tufte, Envisioning Information

Escher - Print Gallery (1956)
Escher drawings revel in the interplay and contradictions inherent in the representation of complex three dimensional space on the picture plane. Like Escher figures, information designs explore the relationship between the medium of representation and object, but one must be literate in information graphics to appreciate this rich interplay between representation and object.

All information graphics make assumptions, simplifications, and tricks which remain invisible to readers without literacy in information graphics. People lacking fluency in information graphics are able to see only what protrudes up out of the ocean, while the remaining meaning lies underneath, an invisible mass of meaning, conventions, and simplifications.
These tricks are material necessities of information visualization which, by nature, seeks to modulate complex realities through readable abstractions and simplifications. Conventions such as false color and scale are necessary for solving problems of presentation and cognition.

In order to properly read and write information graphics one must become literate in the language they speak. One must not only be capable of reading the information they present, their intended meaning, but fluent in reading the invisible information these graphics contain: the producers background, tradeoffs made for visualization purposes, data sources, and the entire array of visualization tricks information graphic designers use.