We present the mapping and data transformation capabilities of LinkEHR-Ed, a visual tool to construct formal definitions of medical concepts in the form of archetypes which can be defined on the basis on multiple electronic health record architecture such as ISO 13606. With LinkEHR-Ed, users can enrich archetypes with mapping information which captures the relationship between relational or XML data sources and archetype structures. This mapping information is then analyzed and compiled into an XQuery expression that transforms source instances into an XML document. The target document satisfies the constraints imposed by the archetype and at the same time is compliant with the underlying electronic health record architecture.