Efficient genealogical graph layout

Abstract

While a visual unconstrained tree structure planar layout design is easy to implement, a visualization of a tree with constraints on node ranks and their ordering within ranks leads to a difficult combinatorial problem. A genealogical graph, such as family tree, can be taken as an example of such a case. Classical ancestor trees, descendant trees, Hourglass charts, and their visual variants such as node-link diagrams or fan charts are suitable for assessment of peoples relationships when one is focused on a particular person and his/her direct ancestors and descendants. Such tree-based representations miss a broader context of relationships and do not allow the quick assessment of several interlinked families together.We propose a new undirected tree-driven layout technique for layered multitree graph visualizations producing constraints on node layers and ordering of groups of nodes within layers. The computed constraints can be mapped, at least partially, into the DOT language property directives used by the Graphviz toolbox. We demonstrate achievements on several datasets containing up to 39000 people.