MSSQ: Manhattan Spatial Skyline Queries

Skyline queries have gained attention lately for supporting effective retrieval over massive spatial data. While efficient algorithms have been studied for spatial skyline queries using the Euclidean distance, these algorithms are (1) still quite computationally intensive and (2) unaware of the road constraints. Our goal is to develop a more efficient algorithm for L-1 distance, also known as Manhattan distance, which closely reflects road network distance for metro areas. We present a simple and efficient algorithm which, given a set P of data points and a set Q of query points in the plane, returns the set of spatial skyline points in just O(vertical bar P vertical bar log vertical bar P vertical bar) time, assuming that vertical bar Q vertical bar <= vertical bar P vertical bar. This is significantly lower in complexity than the best known method. In addition to efficiency and applicability, our algorithm has another desirable property of independent computation and extensibility to L-infinity norm distance, which naturally invites parallelism and widens applicability. Our extensive empirical results suggest that our algorithm outperforms the state-of-the-art approaches by orders of magnitude. We also present efficient algorithms that report the changes of the skyline points when single or multiple query points move along the x- or y-axis. (C) 2013 Elsevier Ltd. All rights reserved.X1199Nsciescopu