This archive contains a set of mappings in X3ML format between a number of metadata record schemes and CERIF RDF (based on CERIF 1.6). These mapping files were created during the EU Horizon 2020 VRE4EIC project as part of the development of a joint catalogue for resources hosted by various European research infrastructures serving the environmental and earth sciences. The following source metadata schemes are supported: Dublin Core DCAT-AP EPOS DCAT-AP (extension of DCAT-AP used within the EPOS research infrastructure) ISO 19139 OIL-E (Open Information Linking for Environmental research infrastructures) The scheme used by EUDAT's B2FIND service (based on CKAN) The scheme used within the D4Science platform (based on CKAN) In addition, test mappings have been developed for the transformation of RBAC data, WADL specifications, and WSDL (both 1.1 and 2.0), transformation of CERIF and VRE4EIC classification schemes into CERIF RDF, and generation of additional provenance data for data originating from EPOS or the ENVRI environmental research infrastructure cluster. To make use of these mappings, it is necessary to have a means of interpreting X3ML documents. See: https://github.com/isl/x3ml To directly view and edit these mappings, as well as to test them, it is best to use the 3M editor (which interprets X3ML). See: https://github.com/isl/Mapping-Memory-Manager 3M can be set up and run as an online service in Apache Tomcat (version 8 or higher). These mappings are provided to interested parties who wish to replicate or build upon the metadata mapping activity of the VRE4EIC project, or wish to import metadata records from external sources into a single RDF triple store structured according to the CERIF 1.6 standard. They represent the best state of mappings as of the end of the VRE4EIC project, in October 2018, but are provided as-is, with no assertion of completeness, soundness or fitness-for-purpose out of the box. For queries regarding the mappings in this archive, or for information about the VRE4EIC project in general, email vre4eic-contact at ercim dot eu.