Semantic Web Geoportal: a Case Study of Ontology Driven Kenya National Spatial Data Infrastructure

Abstract

This research has dealt with one of the geospatial data sharing problems namely, semantic interoperability. The motivation of this research is the current Kenya National Spatial Data Infrastructure (KNSDI) that is being implemented and which require open and interoperable systems. The last few decades have shown a major shift in computing from stand-alone software systems to networked ones. There is an increasing need for organizations to perform on demand geo-processing tasks by integrating and reusing geo-information and geoservices from within and outside the organization. These services are best perfomed within a Spatial Data Infrastructure (SDI) The current state-of-art technology for sharing geospatial information is Geospatial Web Services. Effective use of geo-information requires easy access to metadata that describes the geospatial data and services. However, current descriptions of data and services advanced by KNSDI do not provide the semantics or meaning of the data content and therefore are not sufficient to allow semantic interoperability. For KNSDI to be effective overcoming semantic interoperability problem is an issue that requires a solution. To address this problem, the research deals with developing an ontology, entailing a common vocabulary for concepts and the relationships between them in an SDI. Using protege ontology editor the concepts are mapped as classes and their properties and facets specified. Lastly, instances which are the actual metadata in an SDI are keyed into the prototype. From the prototype it is possible to query for different properties of the metadata. From this research it can be concluded that ontologies can be used in organizing metadata in software application to support interoperable machine to machine interaction over a network. It is recommended that the proposed KNSDI makes use of ontologies in presenting its data and metadata. KEYWORDS Ontology, Semantics, Spatial Data Infrastructure, GIS and metadata