What is visualisation?

This article proposes that the practice of information visualisation (infovis), from its beginnings in the second part of the eighteenth century until today, relied on two key principles. The first principle is reduction. Infovis uses graphical primitives such as points, straight lines, curves and simple geometric shapes to stand in for objects and relations between them. The second principle is the use of spatial variables (position, size, shape and, more recently, movement) to represent key differences in the data and reveal patterns and relations. Following this analysis, the author discusses a more recent visualisation method which we can call 'direct visualisation' (or 'media visualisation'): creating new visual representations from the actual visual media objects (images, video) or their parts. The article analyses the well-known examples of artistic visualisations that use this method: Listening Post (Ben Rubin and Mark Hansen), Cinema Redux (Brendan Dawes) and Preservation of Selected Traces (Ben Fry). It further suggests that direct visualisation is particularly relevant for humanities, media studies and cultural institutions. Using the actual visual artefacts in visualisation as opposed to representing them by graphical primitives helps the researcher to understand meaning and/or cause behind the patterns she may observe, as well as to discover additional patterns. To illustrate this idea, examples of projects created in the author's lab at UCSD (softwarestudies.com) are presented. Founded in 2007, the lab works on techniques and software to allow interactive exploration of large sets of visual cultural data using a direct visualisation approach and supervisualisation systems such as 215 megapixel HIPerSpace. The examples of its work are visualisations of 4553 covers of every issue of Time magazine published between 1923 and 2009; visualisations of all pages of every issue of Science and Popular Science magazines published between 1872 and 1922; and a set of visualisations of 1 million pages on Manga series.