Estimated reading time: 2 minutes

Summary

There are no firm or generally accepted rules for how to visualise data
Human perception is the best guide

There are no firm or generally accepted rules for how to visualise data. Guidelines, if they exist at all, tend to emerge as a result of necessity, only to later be accepted as standard practice within a field.

An example of this is how one professor in biochemistry, Jane S. Richardson, chose to represent beta sheets, as well as the either parallel or anti-parallel connections between the parts of the peptide chain, as arrows. She described this in an article in Nature as early as 1977.

Ribbon diagram of the 3D structure of the protein triose-phosphate isomerase by Jane S. Richardson (1981).

Source: Wikimedia Commons (CC BY 3.0).

Richardson's visual language has ever since so dominated the visualisation of proteins that it appears in most of the digital tools used today to visualise molecules in ribbon diagrams. It has become a standard and practice that fulfills a specific disciplinary need.

To find a more general and trans-disciplinary theoretical foundation to build upon, we'll have to turn to human perception.

Human visual perception is often described as a multi-stage process, where we use our previous experiences and understanding of the world to make sense of what we see. The time, effort and focus needed may vary. Imagine yourself driving a car. If a bright red warning light were to start flashing on the dashboard in front of you, you would probably instinctively look at it. In contrast, evaluating what that flashing light actually means and planning and taking appropriate actions could prove quite demanding.

As the authors of A Tour through the Visualization Zoo point out, the human ability to see patterns and spot trends in graphic representations is key in visual communication. It is human perception that determines our ability to discern, for instance, a cluster formation in a relationship diagram, trends in a bar chart, or differently coloured fields in a choropleth map.

Perception furthermore makes possible visual interpretation of the whole as well as the parts of a form or a figure. This motif is a key principle within Gestalt psychology. (For more on this, see Module 2 on graphic principles).

Recommended reading

Jane Richardson, β-Sheet topology and the relatedness of proteins. Nature (1977).
Colin Ware, Information visualization: perception for design, Morgan Kaufmann, 3rd Ed. 2012.