In SocialCom '11:Proc. IEEE 3rd International Conference on Social Computing (October 2011), 19-26.
Visualizations of static networks in the form of node-link diagrams
have evolved rapidly, though researchers are still grappling with how
best to show evolution of nodes over time in these diagrams. This
paper introduces NetVisia, a social network visualization system
designed to support users in exploring temporal evolution in networks
by using heat maps to display node attribute changes over time.
NetVisia's novel contributions to network visualizations are to (1)
cluster nodes in the heat map by similar metric values instead of by
topological similarity, and (2) align nodes in the heat map by events.
We compare NetVisia to existing systems and describe a formative user
evaluation of a NetVisia prototype with four participants that
emphasized the need for tooltips and coordinated views. Despite the
presence of some usability issues, in 30-40 minutes the user
evaluation participants discovered new insights about the data set
which had not been discovered using other systems. We discuss
implemented improvements to NetVisia, and analyze a co-occurrence
network of 228 business intelligence concepts and entities. This
analysis confirms the utility of a clustered heat map to discover
outlier nodes and time periods.