Distance Based Queries in Open Street Map

Volunteered geographic information (VGI) makes available a very large resource of geographic data. The exploitation of data coming from such resources requires an additional effort in the form of tools and effective processing techniques. One of the most stablished VGI is Open Street Map (OSM) offering data of urban and rural maps from the earth. Recently, we have presented a library for querying OSM data with the XML query language XQuery. This library is based on the well-known spatial operators defined by Clementini and Egenhofer, providing a repertoire of XQuery functions which encapsulate the search on the XML document representing a layer of OSM, and make the definition and composition of queries on top of OSM layers easier. In this paper, we will show how to extend the library in order to express distance based queries. Distances will be used either to get layers of objects in a certain distance from a given object, or to express queries involving closeness concepts.