Search interfaces for data discovery are essential in the context of a Geospatial Data Infrastructure. This paper discusses the development of a search interface, aimed at effective searches and an integration of a catalogue function and thematic mapping. For this purpose, the Resources Description Framework (RDF) is used to store the summaries of metadata of geospatial contents. These summaries are indexed based on their topics. Their topic categories are expressed using the RDF schema. The RDF queries and the transformation of results play a prominent role in the visualization of search results as a table, a thumbnail, and a bull's-eye display with possibilities to project footprints of results on top of a basic map and thematic layers. To highlight their matches to the search terms, the Hausdorff distance and the closeness degree were applied respectively to determine the geographic and thematic relevance. Feedback from participants testing the prototype indicated the benefits of the table and thumbnail displays as well as the possibility to combine these displays with metadata and thematic mapping for data discovery. The feedback also confirmed some design challenges in the depictions of relevance and symbolization of metadata.