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Issue No. 10 - October (2010 vol. 22)
ISSN: 1041-4347
pp: 1444-1458
Ken C.K. Lee , The Pennsylvania State University, University Park
Wang-Chien Lee , The Pennsylvania State University, University Park
Hong Va Leong , The Hong Kong Polytechnic University, Hong Kong
In this paper, we present a new type of spatial queries called Nearest Surrounder (NS) queries. An NS query determines the nearest polygon-shaped spatial objects (referred to as nearest surrounder objects) and their orientations with respect to a query point from an object set. Besides, we derive two NS query variants, namely, multitier NS (m-NS) queries and angle-constrained NS (ANS) queries. An m-NS query searches multiple layers of NS objects for the same range of angles from a query point. An ANS query searches for NS objects within a specified range of angles. To evaluate NS queries and their variants, we explore angle-based and distance-based bound properties of polygons, and devise two efficient algorithms, namely, Sweep and Ripple, based on R-tree. The algorithms access objects in an order according to their orientations and distances with respect to a given query point, respectively. They are efficient as they can finish a search with one index lookup. Besides, they can progressively deliver a query result. Through empirical studies, we evaluate the proposed algorithms and report their performance for both synthetic and real object sets.
Spatial query processing, nearest surrounder queries, R-tree, algorithms.

H. V. Leong, W. Lee and K. C. Lee, "Nearest Surrounder Queries," in IEEE Transactions on Knowledge & Data Engineering, vol. 22, no. , pp. 1444-1458, 2009.
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