GeoSPARQL
GeoSPARQL is a model for representing and querying geospatial linked data for the Semantic Web. It is standardized by the Open Geospatial Consortium as OGC GeoSPARQL.
As of version 1.1, published in 2024, a validator for RDF data to meet GeoSPARQL patterns is also supplied, using SHACL as well as a Simple Features hierarchy of geometry classes and a vocabulary of GeoSPARQL rules and functions.
The definition of a small ontology based on well-understood OGC standards is intended to provide a standardized exchange basis for geospatial RDF data which can support both qualitative and quantitative spatial reasoning and querying with the SPARQL database query language.
The Ordnance Survey Linked Data Platform uses OWL mappings for GeoSPARQL equivalent properties in its vocabulary. The data set is a work of the Agile Knowledge Engineering and Semantic Web research group at the University of Leipzig, a group mostly known for DBpedia, that uses the GeoSPARQL vocabulary to represent OpenStreetMap data.
In particular, GeoSPARQL provides for:
- a small topological ontology in RDFS/OWL for representing Features and Geometries
- serializations of geometry position literals
- * Geography Markup Language, well-known text representation of geometry, GeoJSON, Keyhole Markup Language and a placeholder for discrete global grid representations
- Simple Features, RCC8, and DE-9IM topological relationship vocabularies and ontologies for qualitative reasoning, and
- a SPARQL query interface using
- * a set of topological SPARQL extension functions for quantitative reasoning, and
- * a set of Rule Interchange Format Core inference rules for query transformation and interpretation.
Example
The following example SPARQL query could help model the question "What is within the bounding box defined by and ?"PREFIX geo:
PREFIX geof:
SELECT ?what
WHERE
RCC8 use in GeoSPARQL
RCC8 has been implemented in GeoSPARQL as described below:Implementations
There are no complete implementations of GeoSPARQL; however, there are partial or vendor implementations of GeoSPARQL. Currently there are the following implementations:; Apache Marmotta
; Apache Jena
; MarkLogic
;
;
;
;
;
; OpenSahara uSeekM Sesame Sail plugin
;
; QLever
;
; Virtuoso Universal Server
Performance and compliance benchmarking
Benchmarking GeoSPARQL 1.0 and geospatial-enabled triplestores, in general, has been conducted using several approaches.One can distinguish between performance and compliance benchmarks.
The former can reveal whether a triplestore gives a timely answer to a GeoSPARQL query and may or may not check the answer for correctness. The latter checks whether a triplestore gives compliant answers with respect to the definitions of the GeoSPARQL 1.0 standard irrespective of the time the query takes for execution.
Well-known geospatial performance benchmarks include the Geographica and Geographica 2 benchmarks which track the performance of predefined sets of queries on synthetic and real-world datasets. They each test a subset of GeoSPARQL query functions for performance.
Another performance benchmark by Huang et al. assessed the performance of GeoSPARQL-enabled triple stores as part of a spatial data infrastructure.
Compliance benchmarking of OGC standards is usually conducted as part of the OGC Team Engine Test Suite which allows companies to obtain certification for implementing certain OGC specifications correctly.
As of 2021, however, the OGC Team Engine does not provide a set of compliance tests to test GeoSPARQL compliance.
Nevertheless, in 2021, Jovanovik et al. developed the first comprehensive, reproducible GeoSPARQL Compliance benchmark in which nine different triple stores were initially tested.
The results of these first compliance tests along with the software are available on GitHub.
Submission
The GeoSPARQL standard was submitted to the OGC by:- Australian Bureau of Meteorology
- Bentley Systems
- Commonwealth Scientific and Industrial Research Organisation
- Defence Geospatial Information Working Group
- Natural Resources Canada
- Interactive Instruments GmbH
- Oracle America
- Ordnance Survey
- Raytheon
- Traverse Technologies
- US Geological Survey
Future development
With regards to future work, the GeoSPARQL standard states:In 2019, the OGC's GeoSemantics Domain Working Group set out to assess the current usage of GeoSPARQL in different domains in the White Paper "OGC Benefits of Representing Spatial Data Using Semantic and Graph Technologies" and collected initial feature requests to extend GeoSPARQL.
This led to the re-establishment of the GeoSPARQL Standards Working Group with a newly formed working group charter in September 2020. The group is working towards a new release of the GeoSPARQL standard, with non-breaking changes - GeoSPARQL 1.1 - in the summer of 2021, the development of which can be followed on .
At the, held as part of the, an outline of the additions which are likely to be present in GeoSPARQL 1.1 has been presented.
The changes have been further consolidated and summarized in a publication in the ISPRS International Journal of GeoInformation.