Spatial Data Service Discovery And Integration Based On Geo-ontology

With the rapid development of the Internet, and Geographic Information Systems, Remote Sensing, Geographic Positioning System technologies, huge number of geo-spatial datasets have been released as Web services. A big challenge in fulfilling data discovery and integration again these geo-spatial Web services is that the heterogeneity between semantics used during the data organization and publication process performed by different service providers. Open Geospatial Consortium (OGC) has been leading the efforts in standardizing the interface of geo-spatial Web services, such as Web Feature Service (WFS), Web Coverage Service (WCS) and Web Map Service (WMS). This has greatly facilitated the access to heterogeneous distributed data, which may be in different formats. However, we still observe the missing of the semantic description of these service interfaces. Besides the current syntactic definition of these service interfaces, it is desirable to enable a semantic definition of these interfaces to enable the data discovery and integration of these geo-spatial Web services.Although the ontology languages have been approved to be e effective in describing the semantics of geospatial data, it can not be simply applied to feature and coverage datasets provided by WFS services and WCS services respectively. This paper presents a method to enable ontology query on spatial data available from WFS and WCS services. We do not explicitly provide semantic description to each geo-spatial data services. Instead, we have built a reusable ontology database, and on top of this, we have proposed ontology-based semantic similarity degree model and spatial data services discovery model. And using query rewriting, request the WFS and WCS services"Getcapabilities"interface, automatically extract the WFS and WCS services of capabilities schema and data schema as the discovered data sources.This paper summarized the following research and development achievements:1. Analyzed the following key issues towards building the geo-spatial data service integration architecture: construction of the geographic ontology database, description of geo-spatial data services, discovery of geo-spatial data service, and integration of online accessible geo-spatial data.2. Constructed a geographic ontology database, proposed a five-tuple logical structure of the ontology model. Among this model, the concepts of property set and hierarchy structure are highlighted, which establish a foundation for semantic retrieval.3. Proposed a semantic matching model for geo-spatial data services and a discovery model for geo-spatial data services. In the semantic matching model, concepts are compared in terms of their hierarchical structure similarity and their attribute similarity, and on top of this, a semantic similarity model is further proposed to enable the semantic retrieval of geo-spatial data services. In the discovery model, based on the semantic similarity model, a Boolean-based model and a Vector-based model are further presented in comparing service characteristics.4. Proposed a Data Source schema and a Data Integration schema for geo-spatial data services. Based these concepts, a geo-spatial data service integration method is established.Parts of these research and development achievements have been successfully applied in"Marine Environment Information Grid System"and"Spatial Data Services Retrieve System"projects. So far, the practical application of research based on ontology is still very weak, hoping the above perspective can provide a new solution for practical application.