Environmental applications (support for territorial diagnostics, monitoring of practices, integrated management, etc.) have strengthened the case for efforts in the establishment of sharing and mutualisation infrastructures for georeferenced information. Within the framework of these initiatives, our work has led us to design and create a tool for cataloguing resources for environmental applications. This tool can be used to catalogue different types of resources (digital maps, vector layers, geographical databases, documents, etc.) by using the ISO 19115 standard, and offers a search engine for these resources. The goal of this proposition is to improve the relevance of search engines by relying on semantic knowledge (thematic and spatial) of the concerned domains. In the first stage, the proposition consists of helping the user in his search by offering mechanisms to expand on or to filter his query. In the second stage, we use the results obtained and the underlying semantics for a global presentation of the results.