Heterogeneous and Multilayer Network Visualization

In many application domains, such as biology or sociology, analysts are not only interested in the visualization of a single network consisting of nodes and edges which show the relationship between the nodes. In practice, many different networks need to be considered and visually analyzed together. For instance in systems biology, networks are used to structure and combine data. Such networks are usually referred to as Heterogeneous Networks. Often, they can be arranged within a hierarchy of different levels (or layers), such as to represent molecular-biological relationships or to show the interaction of proteins within cells. From the user's point of view, the understanding of the visual display of such Multilayer Networks is a very challenging task.

Navigating across links to adjacent nodes within the same or different layers of heterogeneous networks may be difficult for the user. Novel interaction techniques may help to reduce this navigation complexity. We developed an interaction technique, called Hub2Go, which supports heterogeneous network exploration by automatic camera movements in multiple network views to facilitate the navigation from and to nodes across interconnected networks.
The analysis of heterogeneous networks on multiple levels is usually not done by just one analyst: several people work together—whether it be at one place (co-located) or several places (distributed), or whether it be at one specific period in time or at several different times. We have developed visualization and analysis tools which support such collaborative work, record analysis sessions, support annotations by the users, and provide some guidance during the analysis process.