Graph drawing plays an important role in the solution of many information visualization problems. Most of the graph drawing algorithms are accompanied by a theoretical analysis of their characteristics, but only extensive experimentations can assess the practical performance of graph drawing algorithms in real-life applications. In this paper, we describe the results of some of the most popular experimental studies on graph drawing algorithms. Each study presents an in-depth comparative analysis on a specific class of algorithms, namely, algorithms for orthogonal drawings, interactive algorithms, algorithms for hierarchical drawings, and force-directed and randomized algorithms. Copyright © 2000 John Wiley & Sons, Ltd.

We give a characterization of all the planar drawings of a triangular graph through a system of equations and inequalities relating its angles; we also discuss minimality properties of the characterization. The characterization can be used: (1) to decide in linear time whether a given distribution of angles between the edges of a planar triangular graph can result in a planar drawing; (2) to reduce the problem of maximizing the minimum angle in a planar straight-line drawing of a planar triangular graph to a nonlinear optimization problem purely on a space of angles; (3) to give a characterization of the planar drawings of a triconnected graph through a system of equations and inequalities relating its angles; (4) to give a characterization of Delaunay triangulations through a system of equations and inequalities relating its angles; (5) to give a characterization of all the planar drawings of a triangular graph through a system of equations and inequalities relating the lengths of its edges; in turn, this result allows us to give a new characterization of the disc-packing representations of planar triangular graphs.

We give a characterization of all the planar drawings of a triangular graph through a system of equations and inequalities relating its angles, solving a problem that is explicitly mentioned as open by several authors; we also discuss minimalit y properties of the charact erization.The characterization can be used: (1) to decide in linear time whether a given distribution of angles between the edges of a planar triangular graph can result in a planar drawing; (2) to tackle the problem of maximizing the minimum angle of the drawing of a planar triangular graph by studying the solution-space of a non-linear optimization problem; (3) to give a characterization of the planar drawings of a triconnected graph through a system of equations and inequalities relating its angles; (4) to give a characterization of Delaunay triangulations through a system of equations and inequalities relating its angles; (5) to give a characterization of all the planar drawings of a triangular graph through a system of equations and inequalities relating the length of its edges; in turn, this result allows to give a new characterization of the disc packing represent ations of planar triangular graphs.