
Data visualization is a subject in computer science that deals with the use of interactive, sensory (audiovisual) representations of abstract data to reinforce cognition, hypothesis building and reasoning. In their words, data visualization is the graphical presentation of information, with the goal of providing the viewer with a qualitative understanding of the information contents [1]. We know data is abstract, but can we reagrd piles of books as abstract too? In the sea of knowledge books are physical, yet without flipping book covers and browsing book pages, they could be seemed as an abstract database.
(pic found from here)