Transformation and linking of authoritative multi-scale geodata for the Semantic Web : a case study of Swedish national building data sets

Abstract: Semantic Web technology has attracted much interest for its ability to integrate and deliver information from different sources, and increasingly, geodata are being published as triple data according to the graph structure laid out in the Resource Description Framework (RDF). Although the Semantic Web already contains a large volume of geotagged information, there is still a lack of suitable geometric representations for proper visualization thereof. Data held by national mapping agencies and other authoritative bodies would therefore be an invaluable addition, since they are typically of high quality and often produced at multiple scales. This thesis presents a case study where the feasibility of bringing authoritative multi-scale geodata to the Semantic Web is investigated through a practical implementation involving nationally maintained Swedish building data sets. Three polygon-based products, each intended for display at a certain scale level, were transformed into RDF using a combination of GeoSPARQL and draft INSPIRE vocabularies. To test integration with other sources, the building data were linked with the community-maintained gazetteer GeoNames. The transformed and linked data were then uploaded to a triplestore, and from there, they were queried and visualized in a web map. The case study shows that the selected data sets can be brought to the Semantic Web for enhanced visualization of related information, but careful planning and harmonization of the original data should preferably precede the transformation process. Furthermore, they show that current geospatial vocabularies are largely suitable for the task, but will need some refinement and added capabilities before extensive data publication can commence.