The design of information can be understood as visual rhetoric. While often used in the pejorative sense, rhetoric means the art of speech and writing. As Hugues C. Boekraad writes in his essay in Copy Proof, rhetoric lessens or erases the distance between the message and the recipient. That is what communication design, at least in practice, sets out to achieve, and information design should be no different. The quality of the message being communicated is entirely dependent on intent, or, in other words, visual rhetoric.
One pillar of rhetoric is the idea, which forms the basis for information collection and concept development. The idea often colors the design process and imbues it with the author’s perspective. The opposite of transparency, the voice of the designer collides with the voice of the information or content. The rhetorical idea is inherently a critique of any content, and provides a layer of interpretation for the recipient.
Like any form of communication design, information visualization relies on the idea as a starting point. In accordence to intent, the voice of the author will permeate the process, from data collection and frameworks through expression and media.
[...] Information visualization is a case in point. As I have mentioned earlier, visualization is inherently subjective, from the choice of data to its expression. Choices are made throughout the entire process, and there is always an intent driving them. In a recommendation age, information design plays the important role of providing supporting evidence for the recommendation. With so much information to parse, visualization is becoming increasingly necessary for communicating the attributes and behaviors of large datasets. And being a rhetorical device, information visualization itself carries the potential to build trust with the recipient. [...]