In chapter 4 of Graphesis, author Johanna Drucker explained what interface is by showing the term's development and theory throughout history. Throughout the chapter, Johanna kept coming back to the idea that in order to understand what interface is, we have to pay attention to the tension between the idea that interface is a restricted canvas that shows different functions of a digital product and the idea that interface is the experience that users have while using it. The former idea derived from the origin of interface, when interface was designed mainly for the purpose of engineer. However, interface studies has becoming more and more human-centered. Psychology and sociology play a big role in shaping interface. And this moved designing interface closer to graphic design or media than just pure engineering.
My first impression of the chapter was even though the writing is very academic and took me a long time to comprehend, I found the chapter very interesting. I am an UX designer so some concepts explained in the chapter for example "affordance", "user experience", or "reading experience" is quite familiar. However, the chapter is not really a guideline but more about explaining these concepts in the context of different works and ideas of different authors throughout the history. It is helpful to look back and see how those concepts evolve in the past few decades.
In term of applying this chapter into data visualization, I think this chapter is really helpful because nowadays, most of data visualization is done and viewed digitally so data visualizers must take into consideration of how viewers will look at those data in the browser in comparison of how people looked at charts on paper in the past.