Above is a plan of London's Soho District (1845) that demonstrates what University of Lugano Communication Science professor Riccardo Mazza calls Graphics for Explorative Analysis:
"Graphics are also a mean for finding and identifying structures and properties in a given data set (Card, et al, 1999). The special properties of visual perception of data may facilitate the finding of relationships, trends, revealing hidden patterns, or as Bertin (1981, p. 16) says, 'it is the visual means of resolving logical problems.' To illustrate. . . [on this map] black dots represent individual deaths from cholera and "x" marks the position of the water pumps. The map allowed Dr. John Snow to observe that most of the deaths . . . were concentrated around the Broad Street water pumps, which was discovered to be the source of diffusion of cholera in the area (Tufte, 1983)." [Visual Literacy Demo Tutorial: Visualization for Engineering and Communication. Viewed 20.04.2009 at http://www.visual-literacy.org/pages/demo.htm].
To read more on visualization/nomenclature/academics of, click here for the group's recommended reading list.