The research agenda related to the interoperability of geospatial data is influenced by the increased accessibility of geospatial databases on the Internet, as well as their sharing and their integration. Although it is now possible to get and use geospatial data independently of their syntax and structure, it is still difficult for users to find the exact data they need as long as they do not know the precise vocabulary used by the organizations supporting geospatial databases. It is now a necessity to take into consideration the semantics of geospatial data to enable its full interoperability. To this end, we designed a new conceptual framework for geospatial data interoperability and introduced the notion of geosemantic proximity based on human communication and cognition paradigms. This paper reviews this framework and the notion of geosemantic proximity. It also presents the GsP Prototype, which demonstrates the relevance of our framework and of the notion of geosemantic proximity for geospatial data interoperability. More specifically, we describe the architecture of the GsP Prototype, its implementation, and tests that have been conducted.