We propose a heuristic for dynamic hierarchical graph drawing. Applications include incremental graph browsing and editing,
display of dynamic data structures and networks, and browsing large graphs. The heuristic is an on-line interpretation of
the static layout algorithm of Sugiyama, Togawa and Toda. It incorporates topological and geometric information with the objective
of making layout animations that are incrementally stable and readable through long editing sequences. We measured the performance
of a prototype implementation.