Authors:
Hansjörg Schmauder
;
Michael Burch
and
Daniel Weiskopf
Affiliation:
University of Stuttgart, Germany
Keyword(s):
Partial Links, Dynamic Graph Visualization, Time-varying Data.
Related
Ontology
Subjects/Areas/Topics:
Abstract Data Visualization
;
Computer Vision, Visualization and Computer Graphics
;
General Data Visualization
;
Graph Visualization
;
Information and Scientific Visualization
Abstract:
Graphs are traditionally represented as node-link diagrams, but these typically suffer from visual clutter when
they become denser, i.e. more vertices and edges are present in the data set. Partial link drawings have been
introduced for node-link diagrams aiming at reducing visual clutter caused by link crossings. Although this
concept was shown to perform well for some parameter settings, it has not been used for visually encoding
dynamic weighted digraphs. In this paper we investigate the problem of visualizing time-varying graphs as
one node-link diagram in a specific layout by exploiting the links as timelines. Partially drawn links are used
to show the graph dynamics by splitting each link into as many segments as time steps have to be represented.
Conventional 2D layout algorithms can be applied while simultaneously showing the evolution over time.
Color-coded links represent the changing weights. We use tapered links to reduce possible overlaps at the link
target nodes that wo
uld occur when using traditional arrow-based directed links. We experiment with different
graph layouts and different numbers of data dimensions, i.e. number of vertices, edges, and time steps. We
illustrate the usefulness of the technique in a case study investigating dynamic migration data.
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