Visualizing Graphs as Maps with Contiguous Regions

Relational datasets, which include clustering information, can be visualized with tools such as BubbleSets, LineSets, SOM, and GMap. The countries in SOM-based and GMap-based visualizations are fragmented, i.e., they are represented by several disconnected regions. While BubbleSets and LineSets have contiguous regions, these regions may overlap, even when the input clustering is non-overlapping. We describe two methods for creating non-fragmented and non-overlapping maps within the GMap framework. The first approach achieves contiguity by preserving the given embedding and creating a clustering based on geometric proximity. The second approach achieves contiguity by preserving the clustering information. The methods are quantitatively evaluated using embedding and clustering metrics, and their usefulness is demonstrated with several real-world datasets and a fullyfunctional online system at gmap.cs.arizona.edu.