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Overview
GeoSPARQL is a standard for representation and querying of geospatial linked data for the Semantic Web from the Open Geospatial Consortium (OGC).The standard provides:
- a small topological ontology in RDFS/OWL for representation using Geography Markup Language (GML) and Well-Known Text (WKT) literals
- Simple Features, RCC8, and DE-9IM (a.k.a. Egenhofer) topological relationship vocabularies and ontologies for qualitative reasoning
- a SPARQL query interface using a set of topological SPARQL extension functions for quantitative reasoning
A simplified diagram of some geometry classes and properties:
GraphDB 6.X introduces support for GeoSPARQL.
Installation
The GeoSPARQL support is implemented as a GraphDB plugin, which is currently not included by default. To include the plugin follow these steps:
- Locate the plugin zip file in the plugins/geosparql-plugin folder of the GraphDB distribution.
- Unzip the file into your plugins directory (by default root_of_unpacked_web_app/WEB-INF/classes/plugins).
Usage examples
Plugin control predicates
The plugin allows you to configure it through SPARQL-Update queries with embedded control predicates:
Enable plugin
NOTE: The object literal can be written also as an xsd boolean type by including a xsd prefix:
Disable plugin
NOTE: The object literal can be written also as an xsd boolean type by including a xsd prefix:
Force Reindex GeoSPARQL geometry data
Usually this is a configuration option which could be used in cases where your index files
are either corrupted or have been mistakenly deleted.