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Re: Geo-DCAT application profile

From: Andrea Perego <andrea.perego@jrc.ec.europa.eu>
Date: Tue, 17 May 2016 11:10:58 +0200
To: Bill Roberts <bill@swirrl.com>
Cc: "public-sdw-wg@w3.org" <public-sdw-wg@w3.org>
Message-id: <5693890d-827f-ba0f-55c9-cb59929a685f@jrc.ec.europa.eu>
Hi, Bill.

I've actually chaired the GeoDCAT-AP WG, who released the final version 
of the specification (1.0) last December:

https://joinup.ec.europa.eu/asset/dcat_application_profile/asset_release/geodcat-ap-v10

Its XSLT implementation, the related API and additional documentation 
are available from:

https://webgate.ec.europa.eu/CITnet/stash/projects/ODCKAN/repos/iso-19139-to-dcat-ap/

GeoDCAT-AP is already included in the SDW UCR document (Section 4.42), 
and there's also a placeholder in the BP.

In July 2015, I've shared an outline of the work done possibly relevant 
to the SDW WG:

https://lists.w3.org/Archives/Public/public-sdw-wg/2015Jul/0082.html

I take this opportunity to summarise below what has happened afterwards:


GEOMETRIES / BOUNDING BOXES

No news. The approach is still the one reported in the following mail:

https://lists.w3.org/Archives/Public/public-sdw-wg/2015Jun/0167.html

As said there, the adopted solution highlighted the lack of an agreed 
way in RDF of specifying that a geometry is a bounding box (or a 
centroid, etc.).


REFERENCE SYSTEMS

The modelling of reference systems in GeoDCAT-AP reflects how this 
information is specified in ISO 19115, as I mentioned here:

https://lists.w3.org/Archives/Public/public-sdw-wg/2016Apr/0061.html

Basically, a reference system is denoted both as a dct:Standard and as a 
skos:Concept, linked to the reference register by using skos:inScheme. 
Moreover, dct:type is used to specify whether it is a spatial or 
temporal reference system, by using the relevant terms (skos:Concept's) 
from the glossary of the INSPIRE Registry.

For instance, this could be a description of EPSG:32630:

<http://www.opengis.net/def/crs/EPSG/0/32630>
     a dct:Standard, skos:Concept ;
     dct:type 
<http://inspire.ec.europa.eu/glossary/SpatialReferenceSystem> .
     dct:identifier 
"http://www.opengis.net/def/crs/EPSG/0/32630"^^xsd:anyURI ;
     skos:prefLabel "WGS 84 / UTM zone 30N"@en ;
     skos:inScheme <http://www.opengis.net/def/crs/EPSG> .

<http://www.opengis.net/def/crs/EPSG>
     a skos:ConceptScheme ;
     dct:title "EPSG coordinate reference systems"@en .

dct:conformsTo is used to specify the reference system(s) used in a 
given dataset.

The description above is not addressing some of issues discussed by the 
WG back in May 2015 - e.g., how to specify the axis order [1] - but it 
could be a starting point. E.g., for temporal reference systems, it can 
be complemented with the relevant terms in the recent version of the 
Time Ontology prepared by Simon - I'm thinking, in particular, to 
time:TRS and time:hasTRS.


SPATIAL RESOLUTION

Recent discussion with the DWBP WG led to a possible solution, based on 
the Data Quality Vocabulary. The thread starts at:

https://lists.w3.org/Archives/Public/public-sdw-comments/2016Mar/0007.html

The relevant section of the DQV specification is 5.13 (ED on GH):

http://w3c.github.io/dwbp/vocab-dqg.html#ExpressDatasetAccuracyPrecision


DATA QUALITY

This is just indirectly related to SDW. However, there was some 
discussion with the DWBP WG on how to express conformance test results 
and conformance levels in DQV. This was a long thread, started in August 
2015 [2]. The current situation is described in the following message 
from Antoine Isaac:

https://lists.w3.org/Archives/Public/public-dwbp-wg/2016Apr/0079.html


Cheers,

Andrea

----
[1]https://lists.w3.org/Archives/Public/public-sdw-wg/2015May/0084.html
[2]https://lists.w3.org/Archives/Public/public-dwbp-wg/2015Aug/0146.html


On 14/05/2016 19:09, Bill Roberts wrote:
> Hi all
>
> An EU group is working on 'Geo DCAT' - an extension/profile of DCAT for
> describing geographical datasets - and related to EU INSPIRE standards.
>
> https://joinup.ec.europa.eu/node/139283/
>
> Anyone in the SDW group closely involved in this?  Obviously there is
> some overlap with some of our metadata related best practices.
>
> Latest working draft downloadable here:
>
> http://joinup.ec.europa.eu/site/dcat_application_profile/GeoDCAT-AP/GeoDCAT-AP_2015-10-12_7th_WG_Draft/
>
> Should we be engaging with this group?  Do we want to take account of
> their (draft) recommendations?
>
> Cheers
>
> Bill

-- 
Andrea Perego, Ph.D.
Scientific / Technical Project Officer
European Commission DG JRC
Institute for Environment & Sustainability
Unit H06 - Digital Earth & Reference Data
Via E. Fermi, 2749 - TP 262
21027 Ispra VA, Italy

https://ec.europa.eu/jrc/
Received on Tuesday, 17 May 2016 09:11:42 UTC

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