Central-Layout Sunburst Algorithm for Hierarchical Data Visualization

Sunburst is an emerging hierarchical data visualization method, which has a clear advantage in the representation of hierarchical structure and attribute relations. In order to solve the problem of unbalanced graph distribution in the visualization of classical sunburst algorithm, a central-layout sunburst algorithm (CLSA) was put forward. First the measurement method of node centrality was proposed, and the child nodes were rearranged considering the characteristics of normal distribution curve, so that the symmetry of graphs on both sides of the central axis of the node and the prominence of specific child nodes could be achieved at the same time. Then, on the basis of node layout for the non-root nodes, the definition of annular sector gravity was proposed, with the rearrangement of the first-level annular sector guided by the principle of minimizing the resultant force. At last, the overall central layout was realized based on multiple strategies. The results of the comparative experiment using the hierarchical data such as GDP of different administrative divisions in 2019 show that CLSA can effectively improve centrality for non-root nodes. For the root node, CLSA can generate a layout in which the annular sectors extend evenly in all directions with high efficiency, and thus ensure the balance of the overall and local graph distribution in the sunburst plane.