RE: Conneg definition was: Re: Start of profiles analysis page - 2nd reply

If I understand the discussion, I think we are talking about two types of profiles:


1. A metadata profile that the DCAT description conforms to – this is what DCAT-AP-EU and the national and regional profiles in Europe are about – to allow a consumer/harvester of metadata to ask for a particular view of the metadata
2. A data profile that the data in the file described using DCAT conforms to, to allow software that wants to fetch the data to get a particular view of the data


In DCAT-AP-EU, there are two properties to support these types:


* The property dct:conformsTo for dcat:CatalogRecord to point to the metadata profile (e.g. DCAT-AP-EU)
* The property dct:conformsTo for dcat:Distribution to point to the data profile


Should we make that distinction clear in our discussion?




From: Rob Atkinson [] 
Sent: 09 December 2017 01:33
To: Annette Greiner <>
Subject: Re: Conneg definition was: Re: Start of profiles analysis page - 2nd reply


Negotiation of a distribution (selecting a distribution given a dcat dataset and profile identifiers,  implies a some form of data access api supported by dcat.. thats a long stretch compared to exposing profile identifiers for distributions in dcat, and allowing negotiation for a specific distribution which supports multiple profiles.



Negotiation mechanisms consistent with these identifiers could be driven by dcat or by the distribution endpoints. 


An api to interact with Dcat metadata graphs could be defined of course, if we felt it was critical, and we could get two independent implementations. .. but should be a new deliverable.








On 9 Dec 2017 08:42, "Annette Greiner" < <> > wrote:

Oh, maybe I misunderstood. Is the DCAT-AP for Europe a true parent of these other DCAT-AP-Xs? I was thinking of the (nonexistent) DCAT-AP as a general parent of DCAT-AP for Europe as well the others. That is what I was thinking doesn't exist. The namespacing here is very confusing.

On 12/8/17 8:12 AM, Karen Coyle wrote:

I'm not sure what you mean by "flat". I'd say that DCAT-AP is an AP, but
since there's no particular "standard" or "guidance" for APs, it is
self-defined in terms of its mode of expression of the content of the
AP. Does that make sense?


On 12/8/17 7:59 AM, Annette Greiner wrote:

Except that there is no such thing as a profile called DCAT-AP, right? The space is still flat.

Sent from my iPhone

On Dec 8, 2017, at 3:42 AM, < <> > < <> > wrote:

Hi Karen - the data.  And yes, inheritance too.

-----Original Message-----
From: Karen Coyle [ <> ]
Sent: 08 December 2017 11:21
To: <> 
Subject: Re: Conneg definition was: Re: Start of profiles analysis page - 2nd reply

Peter, are you referring to the data that is coded using that AP, or the
AP itself? As far as I know, if you want the data coded in DCAT-AP but
not DCAT-AP-IT the site providing the data would need to be able to
create the DCAT-AP-only dataset. If they cannot, then you could accept
DCAT-AP-IT and perform the limiting to DCAT-AP at your end. (This also
brings up the notion of cascading/inheriting in APs, another sticky
topic on our plate.)


On 12/8/17 2:52 AM, <>  wrote:
So in a DCAT-AP context we are getting national catalogues with refinements on the core DCAT-AP.  AFAIK there is a DCAT-AP-IT for italy, and a DCAT-AP-SK for Slovakia.  The convention seems to be developing in this way using a 2char country code.

If I want to merge then perhaps I just want the DCAT-AP version without any country-specific additions.

Would this be an appropriate and testable use case for this?

-----Original Message-----
From: Karen Coyle [ <> ]
Sent: 08 December 2017 10:38
To: <> 
Subject: Conneg definition was: Re: Start of profiles analysis page - 2nd reply

Annette, thanks for the reality check. And as Ruben says, the main aim
is to access data that matches one or more application profiles.

On 12/8/17 1:24 AM, Ruben Verborgh wrote:
Hi Annette,

In my mind, the conneg bit that's needed is about adding the ability to negotiate not the profile itself but the distribution (of a dataset) that supports a preferred profile.

The only requirement seems to be:

6.8.3 Profile negotiation
Create a way to negotiate choice of profile between clients and servers

Perhaps that needs to be more specific so that it is clearly about
choosing data that is consistent with a given application profile.


The second is our main aim,
but conneg clearly also makes sense for the profile itself
if that is available in multiple representations.

Content negotiation already has the capability to handle the case of requesting a copy of astrodcat itself as astrodcat.rdf vs astrodcat.xml vs astrodcat.json.

Indeed, it's this mechanism I propose to reuse
(but no need to mandate that).


Karen Coyle <>
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Annette Greiner
NERSC Data and Analytics Services
Lawrence Berkeley National Laboratory

Received on Saturday, 9 December 2017 11:18:40 UTC