Genealogies are frequently stored as XML files or as files that can readily be converted into XML using third party tools. This Demonstration shows how XML representations of genealogies can be readily visualized as graphs.
In visualizing this genealogy of the descendants of United States President George Washington, you can determine whether you wish to show all relationships or only those created by patrilineal or matrilineal descent. You can choose whether you want to show all persons in the genealogy at once or various algorithmically determined communities. You can also decide to exclude "ParentOf" links, which often duplicate "ChildOf" links or "SpouseOf" links, which can sometimes "clutter" a graphic. You also have several options relating to the rendering of the graph: (1) the type of embedding desired; (2) how vertices (persons) are to be visualized; and (3) the font size of any text.
In concept, the code underlying this Demonstration scales to much larger genealogies. In practice, genealogies with less than 2000 or so persons tend to render best.
Genealogies are often stored in "gedcom" files bearing a "ged" suffix. Various tools exist to convert these older-style "ged" files into more modern "XML" files. You can use your browser to find these tools, which may work as an online service, a Java applet, or an application.
Snapshot 1: a spring electrical embedding of the family tree
Snapshot 2: patrilineal lines in the family tree
Snapshot 3: a community in the family tree, showing names