1. Supporting location-based approximate-keyword queries
2. Walid G. Aref and Hanan Samet. 1990 . Efficient Processing of Window Queries in The Pyramid Data Structure. In Proceedings of the Ninth ACM SIGACT-SIGMOD-SIGART Symposium on Principles of Database Systems , April 2-4, 1990 , Nashville, Tennessee, USA. ACM Press, 265--272. Walid G. Aref and Hanan Samet. 1990. Efficient Processing of Window Queries in The Pyramid Data Structure. In Proceedings of the Ninth ACM SIGACT-SIGMOD-SIGART Symposium on Principles of Database Systems, April 2-4, 1990, Nashville, Tennessee, USA. ACM Press, 265--272.
3. SpSJoin
4. Spatio-textual similarity joins
5. Spatial keyword query processing