cardinality of accessURL and downloadURL

[idevisser]

In DCAT-AP 2.1.1 accessURL is mandatory and has the cardinality of 1..n, downloadURL is optional and has the cardinality of 0..n.

In practice, accessURL does not always occur with a distribution, in that case only a download URL is available. Conversely, the downloadURL is not always present either.

What I now see is that as a workaround it is indicated in the various national profiles that in the case there is no accessURL, the downloadURL must also be included in the accessURL, because this property is mandatory. As a result, there will be URLs in the property accessURL that are not accessURL.

I would suggest to include a constraint that one of accessURL or downloadURL is mandatory. The cardinality for both is then 0..n