Rectangular treemaps divide a rectangle and then its subdivisions in a two-dimensional space, and have high space utilization in visualizing large hierarchical datasets. Most current treemaps, however, do not clearly show the relations between the items of the same level. This paper presents a new layout called concentric rings ordered tree (CROT), which hardly wastes any space and also shows sibling relationships clearly. CROT arranges a tree's different levels as rings with the root at the center growing outward and then the nodes of the same ring in clockwise order. CROT also stacks leaf nodes within their parent node. It uses colors to distinguish different branches of the tree. Through a user evaluation experiment, we discuss the characteristics, advantages and limitations of this new approach and a few innovative ideas as the future research.
['Chao Wen', 'Kang Zhang', 'Jie Li', 'Fanrui Sun']
Visualizing Big Hierarchical Datasets on Concentric Rings