Continuous Spatial Query Processing: A Survey of Safe Region Based Techniques

Jianzhong Qi, Rui Zhang, Christian Søndergaard Jensen, Ramamohanarao Kotagiri, Jiayuan He

Research output: Contribution to journalJournal articleResearchpeer-review

7 Citations (Scopus)
103 Downloads (Pure)


In the past decade, positioning system-enabled devices such as smartphones have become most prevalent. This functionality brings the increasing popularity of location-based services in business as well as daily applications such as navigation, targeted advertising, and location-based social networking. Continuous spatial queries serve as a building block for location-based services. As an example, an Uber driver may want to be kept aware of the nearest customers or service stations. Continuous spatial queries require updates to the query result as the query or data objects are moving. This poses challenges to the query efficiency, which is crucial to the user experience of a service. A large number of approaches address this efficiency issue using the concept of safe region. A safe region is a region within which arbitrary movement of an object leaves the query result unchanged. Such a region helps reduce the frequency of query result update and hence improves query efficiency. As a result, safe region-based approaches have been popular for processing various types of continuous spatial queries. Safe regions have interesting theoretical properties and are worth in-depth analysis. We provide a comparative study of safe region-based approaches. We describe how safe regions are computed for different types of continuous spatial queries, showing how they improve query efficiency. We compare the different safe region-based approaches and discuss possible further improvements.
Original languageEnglish
Article number64
JournalA C M Computing Surveys
Issue number3
Number of pages39
Publication statusPublished - 2018


  • Continuous kNN query
  • Continuous range query
  • Moving object
  • Moving query

Fingerprint Dive into the research topics of 'Continuous Spatial Query Processing: A Survey of Safe Region Based Techniques'. Together they form a unique fingerprint.

Cite this