The following is a quick recap on the core classes of EDM.
The edm:ProvidedCHO is the cultural heritage object which has given rise to and is the subject of the package of data that has been submitted to Europeana. Its properties are those of the original cultural heritage object. Strictly speaking, the edm:ProvidedCHO is the resource in Europeana that relate to the original cultural heritage object not its digital representation, for example attributes of the Mona Lisa, not the digitised image of the paintining.
EDM defines edm:Web Resource as ‘information resources that have at least one web representation and at least a URI.’ In this model, the edm:WebResource is a digital representation of an item (e.g. of a printed resource or a born-digital resource). All information about a representation – whether it is born-digital or digitized – has to be provided using an instance of the class edm:WebResource.
The ore:Aggregation serves to group together all important elements of cultural heritage objects contributed by the content providers. Aggregations are used in EDM to represent the complex constructs that are provided by contributors. In compliance with EDM, the fundamental relationships between edm:WebResource and edm:ProvidedCHO are realized by using the ore:Aggregation class. This is the place where the metadata relating to this whole object will be recorded
As mentioned throughout this course, all the classes and properties, the data types that can be used as values and the obligation level of each property are described extensively in the EDM Mapping Guidelines. These guidelines are to be found on the Europeana Data Model Documentation page and should serve as guidance for providers wanting to map their data to EDM. Those interested can find there an example of original data, the same data converted to EDM and diagrams showing the distribution of the properties amongst the classes. The mapping guidelines should be consulted frequently as the full set of EDM classes and properties are being implemented incrementally.
Next, we'll present a mind map of actual MARC21 fields that could be assigned to respective EDM fields and classes. Following that we have a practical example from the National Library of Serbia of creating EDM from their MARC21 records. At the end of the section, we'll take to a more visual trip to see how an object from a library shelf becomes a presence in Europeana.
Please note, that the examples presented here are to serve as guidance and support, and might not always match your data manipulation needs.