Beyond Bertin: Seeing the Forest despite the Trees

Visualization is at a point in its development where its practitioners frequently find themselves grappling with big questions about its nature and purpose. These include fundamental questions about how visualization works-that is, how do people interpret visual forms as information? However, the answers to this question haven´t evolved greatly since visualization´s early days. The classical view is that visualization is a process of encoding numerical or categorical values as visual (or retinal) variables such as size, distance, or color, which the viewer then decodes to reconstruct the original information. This variable-encoding model is the simplified essence of Jacques Bertin´s Semiology of Graphics and the years of visualization theory that have built upon it, including Jock Mackinlay´s work on automated presentation design and Leland Wilkinson´s The Grammar of Graphics.