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Re: DQV, ISO 19115/19157 and GeoDCAT-AP - representing conformance levels

From: Andrea Perego <andrea.perego@jrc.ec.europa.eu>
Date: Tue, 08 Mar 2016 14:31:13 +0100
To: Antoine Isaac <aisaac@few.vu.nl>
Cc: "public-dwbp-wg@w3.org" <public-dwbp-wg@w3.org>
Message-id: <56DED421.4080700@jrc.ec.europa.eu>
Hi, Antoine.

I'm afraid this is another long email - my (recurring) apologies.

On 08/03/2016 10:18, Antoine Isaac wrote:
>
> [snip]
>
> I'm tempted to start discussing in depth these matters, but I'm afraid
> I've got more general questions before - especially now that some time
> has passed and new things appeared.
>
> - what is GeoDCAT-AP really using for degrees of conformance? Annex
> II.14 mentions that INSPIRE Registry maintains a URI set for them, and
> points to section 6. But the link given there in
> http://inspire.ec.europa.eu/codelist/DegreeOfConformity does not work.

Sorry for that - and thanks for reporting the issue!

The actual URI is

http://inspire.ec.europa.eu/metadata-codelist/DegreeOfConformity

We used to have an HTTP redirection in place from /codelist/ to 
/metadata-codelist/ - we'll fix this in the next few days.

> - we are about to add in DQV examples regarding quality policies (draft
> at [1]). Do you think this is closely related to the issues you raised
> here? Should we unify the patterns? At this stage I'd rather avoid the
> extra work, but I do have to check with you.
>
> [snip]
>
> [1]
> https://www.w3.org/community/odrl/wiki/W3C_Data_on_the_Web_Best_Practices_-_Data_Quality_Policy

Yep - I think it's definitely related to the scenarios I was referring to.

If I correctly understand, the idea in [1] is to use ODRL to provide a 
formal description of a quality policy (in this case, an SLA). So, the 
computed quality measurements can be matched against what said in the 
quality policy (_:ex1) to determine whether the relevant resource 
(:myDatasetDistribution) complies with it (:myDatasetDistribution 
dct:conformsTo _:ex1).

Quality measurements and conformance statements could be both seen as 
"observations" (in the broader sense), so aligning their representation 
shouldn't be a problem, conceptually. However, I don't know if the 
current version of DQV can already support this. In particular, two 
points are unclear to me:


1. Can dqv:QualityMeasure be used to express a conformance statement?

This would require, e.g., expressing the quality measure "value" 
(dqv:value) with code lists as those used in ISO, EARL and INSPIRE. 
However, in the examples currently included in DQV, dqv:value is used 
only with literals.

On this issue, it is worth mentioning the ISO approach:

https://geo-ide.noaa.gov/wiki/index.php?title=ISO_Data_Quality

As you can see from the UML diagram, ISO has the notion of data quality 
report (DQ_Element), where the result can be either a quantitative 
result (DQ_QuantitativeResult) or a conformance result 
(DQ_ConformanceResult). As far as I can see, dqv:value models just the 
former (quantitative result).


2. Which is the relationship between dqv:QualityMeasure and 
dqv:QualityPolicy?

I don't know if this is already supported, but I think that an explicit 
relation between these entities will "close the circle" between two 
relevant branches of DQV, making it possible to align the representation 
of quality measures and conformance statements.


About "closing the circle", but on a different part of DQV:

Is there any relationship between dqv:QualityAnnotation, 
dqv:QualityMeasure and dqv:QualityPolicy? This would allow the 
association of a quality annotation (e.g., in the form of a quality 
certificate) with the computed quality measures, demonstrating 
conformance with a given quality standard (e.g., the ODI certificate).


Cheers,

Andrea
Received on Tuesday, 8 March 2016 13:32:01 UTC

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