Analyzing Evolution of Network Attributes and Content with NetFlow: A Network Evolution Visualization Tool

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 NetFlow, a network visualization system designed to support users in exploring temporal evolution in networks by using heat maps to display node attribute changes over time. NetFlow’s novel contributions to network visualizations are (1) to 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 NetFlow to existing systems and describe a formative user evaluation of a NetFlow prototype with four participants emphasized the need for tooltips and coordinated views. However, the user evaluation shows that participants can discover insights about temporal changes in network attributes despite the presence of some usability issues. Despite the presence of some usability issues, in 3040 minutes the user evaluation participants discovered new insights about the data set which had not been discovered using other systems.