IEEE Trans Vis Comput Graph. 2021 Aug;27(8):3571-3584. doi: 10.1109/TVCG.2020.2973564. Epub 2021 Jun 30.
The visualization of hierarchically structured data over time is an ongoing challenge and several approaches exist trying to solve it. Techniques such as animated or juxtaposed tree visualizations are not capable of providing a good overview of the time series and lack expressiveness in conveying changes over time. Nested streamgraphs provide a better understanding of the data evolution, but lack the clear outline of hierarchical structures at a given timestep. Furthermore, these approaches are often limited to static hierarchies or exclude complex hierarchical changes in the data, limiting their use cases. We propose a novel visual metaphor capable of providing a static overview of all hierarchical changes over time, as well as clearly outlining the hierarchical structure at each individual time step. Our method allows for smooth transitions between treemaps and nested streamgraphs, enabling the exploration of the trade-off between dynamic behavior and hierarchical structure. As our technique handles topological changes of all types, it is suitable for a wide range of applications. We demonstrate the utility of our method on several use cases, evaluate it with a user study, and provide its full source code.
随着时间的推移，对层次结构数据进行可视化一直是一个挑战，目前已经存在几种尝试解决该问题的方法。例如，动画或并列树状图等技术无法提供时间序列的良好概述，并且在表达随时间变化方面缺乏表现力。嵌套流图提供了对数据演变更好的理解，但在给定时间步缺少层次结构的清晰轮廓。此外，这些方法通常仅限于静态层次结构，或者排除了数据中的复杂层次结构变化，限制了它们的用例。我们提出了一种新颖的视觉隐喻，能够提供随时间推移的所有层次结构变化的静态概述，同时在每个单独的时间步清楚地勾勒出层次结构。我们的方法允许在 treemap 和嵌套流图之间进行平滑过渡，从而能够在动态行为和层次结构之间进行权衡。由于我们的技术处理所有类型的拓扑变化，因此它适用于广泛的应用。我们在几个用例中展示了我们方法的实用性，通过用户研究对其进行了评估，并提供了其完整的源代码。
