A service-oriented search framework for full text, geospatial and semantic search

Over the last decade, a growing importance of search engines could be observed. An increasing amount of knowledge is exposed and connected within the Linked Open Data Cloud, which raises users' expectations to be able to search for any information that is directly or indirectly contained. However, diverse data types require tailored search functionalities---such as semantic, geospatial and full text search. Hence, using only one data management system will not provide the required functionality at the expected level. In this paper, we will describe search services that provide specific search functionality via a generalized interface inspired by RDF. In addition, we introduce an application layer on top of these services that enables to query them in a unified way. This allows for the implementation of a distributed search that leverages the identification of the optimal search service for each query and subquery. This is achieved by connecting powerful tools like Openlink Virtuoso, ElasticSearch and PostGIS within a single framework.