A Unified Approach to Automatic Label Placement

The automatic placement of text or symbol labels corresponding to graphical features is critical in several application areas such as cartography, geographical information systems, and graph drawing. In this paper we present a general framework for solving the problem of assigning text or symbol labels to a set of graphical features in two dimensional drawings or maps. Our approach does not favor the labeling of one type of graphical feature (such as a node, edge, or area) over another. Additionally, the labels are allowed to have arbitrary size and orientation. We also present a fast and simple technique, based on the general framework, for assigning labels to edges of graph drawings. We have implemented our techniques and have performed extensive experimentation on hierarchical and orthogonal drawings of graphs. The resulting label assignments are very practical and indicate the effectiveness of our approach.