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Geo-spatial Information Science

, Volume 9, Issue 2, pp 118–126 | Cite as

GQL: Extending Xquery to query GML documents

  • Guan Jihong
Article

Abstract

GML is becoming the de facto standard for electronic data exchange among the applications of Web and distributed geographic information systems. However, the conventional query languages (e.g. SQL and its extended versions) are not suitable for direct querying and updating of GML documents. Even the effective approaches working well with XML could not guarantee good results when applied to GML documents. Although XQuery is a powerful standard query language for XML, it is not proposed for queryings spatial features, which constitute the most important components in GML documents. We proposes GQL, a query language specification to support spatial queries over GML documents by extending XQuery. The data model, algebra, and formal semantics as well as various spatial functions and operations of GQL are presented in detail.

Keywords

XML GML spatial feature query language XQuery 

CLC Number

P208 

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Copyright information

© Wuhan University of Technology 2006

Authors and Affiliations

  • Guan Jihong
    • 1
  1. 1.School of ComputerWuhan UniversityWuhanChina

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