Algorithms for the multiple label placement problem

We consider the problem of positioning text or symbol labels associated with graphical features of two dimensional maps (geographical or technical) or drawings. In many practical applications each graphical feature may have more than one label. The need for assigning multiple labels is necessary to display different attributes of an object. Even though many algorithms exist for the labeling problem, very little work has been directed towards positioning multiple labels per graphical feature in a map or drawing. We refer to this problem as the Multiple Label Placement (MLP) problem. In this paper we present a model and expand the rules that govern a good assignment of several labels per graphical feature. In addition we introduce techniques to solve this problem. We have applied these techniques to drawings of graphs, and we present very encouraging experimental results.