Facilitating access to scientific bibliographic collections on the web of data is a major challenge for the sovereignty and scientific collaboration of European countries. The LRM-Factory project aims to create the first metadata factory to facilitate the transition to the semantic web for bibliographic agencies through the mass migration of collections to vocabularies such as RDA. The LRM-Factory project was presented by members of the Medical library Documentation Centrale des Hospices Civils de Lyon at the 6th UNIMARC Users Meeting. Following the presentation From UNIMARC to RDA: LRM-Factory, An Online Mass-migration Tool, we were asked about the difficulties encountered. In this contribution, we would like to answer this question by describing the mapping work carried out as part of the project: the alignment work between UNIMARC relator codes and RDA. After a brief overview of the project and the partners involved, the method used to construct this specific mapping and the tools used are described, and then the three possible levels of alignment that can be observed are dealt with in detail. A special case is briefly mentioned before the conclusion.
