Making attributes from the Linked Open Data (LOD) cloud a part of Spatial Data Infrastructures (SDIS) for thematic mapping
The creation of the linked open data (LOD) cloud has enhanced the availability of interlinked open statistical data associated with geographic regions (attributes) through the Web. Spatial data infrastructures (SDIs) are widely used to share, discover, visualise and retrieve geospatial data. Geoportals are the visible parts of SDIs focused on interoperability through implementing standards such OGC web services for discovery and use of geographic data and services. In the current form OGC services cannot be directly connected to the LOD cloud. This research aimed at finding novel ways of visualising linked data in the form of thematic maps over the Internet. This paper provided answers to the question of how an OGC Web Map Service (WMS) can create thematic maps by combining attributes from the LOD cloud with geometry stored in a spatial database server (SDS). This research contributed to bridging the gap between linked data, SDI and web thematic maps and further showed how existing web mapping and OGC technologies can benefit from the Semantic Web. First, the design of a geospatial web service (representing the visible part of an SDI) that accesses attribute data from the LOD cloud referred to in this paper as SDI-LOD is presented. SDI-LOD produces web thematic maps by programmatically combining attributes from the LOD cloud with geometry in an SDS. Next, the author presented implementation results of SDI-LOD and concluded with a discussion of the implementation. This paper has motivated future work on SDI-LOD to integrating data from internet of things.
Keywords: thematic map; LOD cloud; geospatial data; linked open data; geospatial web service; SDI