Graphics Reference
In-Depth Information
Chapter 12
Flows
Flow visualization can be one of the most intuitive and compelling forms of
visual representation of quantitative information. One of the most famous
examples is Charles Joseph Minard's chart of Napoleon's disastrous 1812
campaign against Russia. Published in 1869, it showed loss of life as troops
marched into battle and later retreated. As shown in
Figure 12-1
, route data
like Minard's or like that used in typical traffic analysis is in most cases not
a graph, but the same graphical techniques of line width and layout apply to
graph data.
Flow is important in understanding systems and patterns of behavior. Flow
visualization can be used to describe the structure and state of a system,
such as a supply chain or an economy. It can also be used for displaying
transactional events, such as information exchange between computers or
money transfers between financial accounts. Flow visualization can also be
used to depict “softer” systems such as behavioral models, showing the
potential influence of various factors in a past, current, or future outcome,
whether that be financial results or the latest sports scores.
