Nested tracking graph for one ensemble member of the viscous finger dataset with highest particle resolution. In contrast to common tracking graphs-where edges only encode the evolution of components for a single level-nested tracking graphs additionally illustrate the nesting hierarchy of components across levels. The x-axis represents time and the y-axis is used to minimize edge crossings. The density levels 25, 30, and 35 are shown from dark to light red, and the width of edges encodes the size of their associated components. Tracking graphs are a well established tool in topological analysis to visualize the evolution of components and their properties over time, i.e., when components appear, disappear, merge, and split. However, tracking graphs are limited to a single level threshold and the graphs may vary substantially even under small changes to the threshold. To examine the evolution of features for varying levels, users have to compare multiple tracking graphs without a direct visual link between them. We propose a novel, interactive, nested graph visualization based on the fact that the tracked superlevel set components for different levels are related to each other through their nesting hierarchy. This approach allows us to set multiple tracking graphs in context to each other and enables users to effectively follow the evolution of components for different levels simultaneously. We demonstrate the effectiveness of our approach on datasets from finite pointset methods, computational fluid dynamics, and cosmology simulations.
This work primarily builds on the nested tracking graph (NTG) REF , a topological abstraction that records the evolution of superlevel set components across time and levels.
Nested Tracking Graphs
Comput. Graph. Forum
Comput. Graph. Forum
Computer Science