Voronoi Evolving Treemaps

Since their invention, treemaps have been widely used to visualize hierarchical structures, due to their intuitive nature and their scaling capability: Indeed, given a maximum treemap size, one can depict hierarchical structures, such as file and software systems, of arbitrary size and depth. To make up for the rather blocky nature of treemaps, Voronoi treemaps were introduced, leading to depictions that look more "organic". However, hierarchical structures in general, evolve over time, and this is especially the case for software. We present Voronoi Evolving Treemaps (VET), a novel approach inspired by the Voronoi power-weighted treemap algorithm, that takes into account the evolution of hierarchical structures. VET is able to display the complete evolution of a software system in terms of its hierarchical structure, and enriches the visualization with additional information. We detail VET's evolutionary layout algorithm, discuss the architecture, implementation, and the features of VET, and illustrate how VET can be used to analyze the evolution of different systems.