Two Ellipse-based Pruning Methods for Group Nearest Neighbor Queries Hongga Li, Hua Lu, Bo Huang, and Zhiyong Huang   View Paper (PDF)   Return to Session 5: Query Processing and Optimization Abstract Group nearest neighbor (GNN) queries are a relatively new type of operations in spatial database applications. Different from a traditional kNN query which specifies a single query point only, a GNN query has multiple query points. Because of the number of query points and their arbitrary distribution in the data space, a GNN query is much more complex than a kNN query. In this paper, we propose two pruning strategies for GNN queries which take into account the distribution of quer ... ©2006 Association for Computing Machinery