Data Visualization

Hierarchical Visualizations or Trees are collections of items with each item having a link to one parent item (except the root). Items and the links between parent and child can have multiple attributes. These can be applied to items and links. Tasks related to structural properties become interesting - how many levels in the tree? or how many children does an item have?

Examples include: dendrogram, phylogenetic tree, radial tree, hyperbolic tree, tree map, cone tree, radial hierarchy, and decision tree/flow chart. What do these look like?  They are among the light green elements on the Periodic Table of Visualization.