Annotating maps, graphs, and diagrams with pieces of text is an important step in information visualization that is usually referred to as label placement. We define nine label-placement models for labeling points with axis-parallel rectangles given a weight for each point. There are two groups; fixed-position models and slider models. We aim to maximize the weight sum of those points that receive a label.
We first compare our models by giving bounds for the ratios between the weights of maximum-weight labelings in different models. Then we present algorithms for labeling n points with unit-height rectangles. We show how an O(n log n)-time factor-2 approximation algorithm and a PTAS for fixed-position models can be extended to handle the weighted case. Our main contribution is the first algorithm for weighted sliding labels. Its approximation factor is (2 + e), it runs in O n 2 /e) time and uses O n/e space. We also investigate some special cases.
|Title of host publication||Algorithms and computation : proceedings 12th international symposium, ISAAC 2001, Christchurch, New Zealand, december 19-21, 2001|
|Editors||P. Eades, T. Takaoka|
|Place of Publication||Berlin|
|Publication status||Published - 2001|
|Name||Lecture Notes in Computer Science|