chapter  9
- Visualization Techniques for Trees, Graphs, and Networks
Pages 22

While most of the visualization techniques discussed thus far focus on the

display of data values and their attributes, another important application of

visualization is the conveying of relational information, e.g., how data items

or records are related to each other. These interrelationships can take many

forms:

• part/subpart, parent/child, or other hierarchical relation; • connectedness, such as cities connected by roads or computers connected by networks;

• derived from, as in a sequence of steps or stages; • shared classification; • similarities in values; • similarities in attributes (e.g., spatial, temporal). Relationships can be simple or complex: unidirectional or bi-directional,

nonweighted or weighted, certain or uncertain. Indeed, the relationships may

provide more and richer information than that contained in the data records.

Applications for visualizing relational information are equally diverse, from

categorizing biological species, to exploring document archives, to studying

a terrorist network.