No need to force providing dcat:dataset for a CSW service

[sgrellet]

We have been asked to provide a dcat:Dataset and dcat:Distribution for WP15 OGC CSW service description.

Let's move to lay man terms for the demonstration and not restrict ourselves to DCAT 20140116 and EPOS_DCAT_AP
{lay man on}
But what is the 'dataset' served by a CSW ?
As opposed to OGC WMS and WFS, a CSW does not serve a 'dataset' per se but the sum of the union of all the metadata records and datasets/services description contained in it.
{lay man off}

According to dcat 20140116, the previous reasoning would imply that is a need for a direct link between dcat:Catalogue and epos:WebService.
And not impose to go through the dcat:Dataset -> dcat:Distribution route

W3C DXWG already discussed and solved the issue here: https://github.com/w3c/dxwg/wiki/Cataloguing-data-services
The corresponding pull request : w3c/dxwg#241

Can we reuse the proposed approach ?

[ltrani]

EPOS-DCAT-AP allows you to describe services independently from the datasets they deliver (if any), thus also independently from a Distribution. In other words there is no imposed path Dataset->Distribution->WebService. Presumably the request you mention was done for the sake of the demonstrator. However, you are free to describe only a service if that is your primary focus.
WebService is a resource and can be linked to a Catalog with the relationship epos:resource. At a first glance this seems to be inline with the solution you refer to.

In your case there might be multiple ways to populate EPOS-DCAT-AP with several entrypoints.
WebService and/or Dataset - Distribution and then link to WebService or even we might consider a mapping with Catalog (see dct:isPartOf relationship on Catalog). In principle all those solutions are feasable, it is a matter of agreements e.g. on the sought level of interoperability.
Let's discuss at the next technical meeting!

[nmtoken]

As opposed to OGC WMS and WFS, a CSW does not serve a 'dataset'

even a WMS doesn't have to act on a single dataset, but could work on many. A layer could be made up of more than one dataset too.