Yang Ou School of GeoSciences The University of Edinburgh

1. Expressing the Semantics of Geographic Information and Processes Yang Ou School of GeoSciences The University of Edinburgh

2. Interoperability Information Processes Syntactic data conversion Spatial Data Transfer Standard (SDTS) Open Geodata Interoperability Specification (OGIS) Web Services Semantic Ontologies Approaches to Achieve GIS Interoperability

3. Describing the Semantics of Geographic Information

4. conceptual level Ontology data level Model 2 Model 3 … Model n Model 1

5. Domain Ontology models implements conceptualises represents Real-world Entities Spatial Database geometry id name … Schemas/Data model geometry id name … Relationship between Representations of Spatial Information

6. implements models Schemas/Data model represents Real-world Entities Spatial Database hasLocation conceptualises conceptualises hasConcept Data Ontology Domain Ontology geometry id name … geometry id name …

7. Part of the Definition of the Data Ontology range range SpatialDataset ≡ Dataset u＝1hasCoordinateSystem VectorDataset ≡SpatialDataset u＝1hasGeometry PointDataset ≡ VectorDataset u8hasGeometry.Point domain domain LineDataset ≡ VectorDataset u8hasGeometry.Line PolygonDataset ≡ VectorDataset u8hasGeometry.Polygon RasterDataset ≡SpatialDataset u:VectorDataset u＝1hasResolution subClassOf subClassOf subClassOf subClassOf subClassOf Basic Conceptualisation of Spatial Dataset in RDFS SpatialDataset hasLocation VectorDataset RasterDataset hasConcept LineDataset PointDataset Literal PolygonDataset

8. To utilise the “semantic information”, we need “semantic processes”.

9. Constructing Semantic Web Services for Geospatial Processes

10. Example: there was a Web service that was providing a process to calculate the distance between two points. Point {double x; double y} double distanceBetween(Point a, Point b);

11. ontological instance Semantic Interface Semantic Web Service SOAP message Syntactic Interface Web Service spatial data Geospatial Process Interoperability Structure for Geospatial Processes

12. describes instance fetch data Input handler dataset Semantic Interface data Atomic Process Syntactic Interface Input Handling Process

13. instance instance Output handler creates describes Semantic Interface stores dataset data Atomic Process Syntactic Interface Output Handling Process

14. Input Handling Process Atomic Geospatial Process Output Handling Process spatial data spatial data instance instance Atomic Geospatial Processing Unit

15. break down into two steps A Running Example Identifying a certain kind of facility near given locations Process 1: Creating buffer areas of the given locations Process 2: Selecting the features that drop within the buffer areas

16. The Processing Unit of the Buffering Process

17. The Processing Unit of the Selection Process

18. Combination of the Two Processing Units

19. Randomly Produced Layers for Testing

20. Virtual Data Source

21. Describing the Datasets in an Ontology

22. specify the buffer distance Output: the URI of the instance that describes the process result choose the layer to be selected choose the layer to be buffered

23. explore the output URI

24. retrieve the spatial data of the process result through the location property in the ontology

25. Visualisation of the Output Data Sets

26. geometry feature_id country_name currency population POLYGON 100 Iceland Krona 267240 record Iceland 100 Krona polygon 267240 name id currency individual geometry population Iceland A Further Idea to Apply Ontologies in GIS Representing Geographic Information as Geographic Knowledge Database vs. Knowledge base

27. geometry feature_id country_name currency population POLYGON 100 Iceland Krona 267240 100 Iceland Krona name string integer id hasValue hasValue string hasValue hasValue hasName hasValue hasName currency hasValue attribute attribute 267240 double hasName polygon hasAttribute attribute population hasValue hasAttribute hasValue hasName hasAttribute attribute hasGeometry hasAttribute Iceland record individual

28. Some potential advantages: • The process of such a kind of semantic geographic information doesn’t require communicating ontologies with spatial data. • Reasoning capability of ontologies can be considered to perform potential geospatial analyses. • Developing Geographic Information Systems towards Geographic Knowledge Systems.

29. Thank you!