XQuery As a Spatial Query Language

Abstract – In this paper, we investigate the use of XQuery to retrieve geographic data represented in GML. The proposed approach is aimed at overcoming the limitations of the earlier proposed GML query languages, and is able to handle any GML data. We start with an analysis to show why among various kinds of XML and non-XML query languages we choose XQuery as a fundamental query language for querying GML data. We then describe the peculiarities of GML data and identify the special requirement for querying GML data which are not sufficiently addressed in XQuery language. Finally, we present an approach to extend XQuery to address semantics, navigation mechanism and data types in GML to support query over GML data