When the correspondences on the plane can be established among all the divisions of the same component, the construction is a network. - Jacques Bertin

Value perception dominates color perception.

Data is transformed into graphics to understand. A map, a diagram are documents to be interrogated. But understanding means integrating all of the data. In order to do this it’s necessary to reduce it to a small number of elementary data. This is the objective of the “data treatment” be it graphic or mathematic.

[Overall level questions involved an] understanding of the deep structure of the data being presented in their totality, usually comparing trends and seeing groupings.