New Approximation Algorithms for Map Labeling with Sliding Labels |
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Authors: | Binhai Zhu ZP Qin |
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Institution: | (1) Department of Computer Science, Montana State University, Bozeman, MT 59717-3880, USA;(2) Department of Mathematics, Huazhong University of Science and Technology, Wuhan, China |
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Abstract: | In this paper we present approximation algorithm for the following NP-hard map labeling problem: Given a set S of n distinct sites in the plane, one needs to place at each site a uniform square of maximum possible size such that all the squares are along the same direction. This generalizes the classical problem of labeling points with axis-parallel squares and restricts the most general version where the squares can have different orientations. We obtain factor-4 and factor-
approximation algorithms for this problem. These algorithms also work for two generalized versions of the problem. We also revisit the problem of labeling each point with maximum uniform axis-parallel square pairs and improve the previous approximation factor of 4 to 3. |
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Keywords: | approximation algorithms map labeling NP-hardness |
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