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Re: BP restructuring: Metadata section

From: Andrea Perego <andrea.perego@jrc.ec.europa.eu>
Date: Tue, 26 Jul 2016 16:55:07 +0200
To: Linda van den Brink <l.vandenbrink@geonovum.nl>, "SDW WG (public-sdw-wg@w3.org)" <public-sdw-wg@w3.org>
Message-id: <c7db742a-0667-0846-4450-f093f4526b57@jrc.ec.europa.eu>
Thanks, Linda.

I would be happy to help here, also with examples.

Some preliminary comments on the listed types of spatial metadata:

 > data type (raster or vector)

Not sure if this completely matches with the ISO 19115 notion of 
"spatial representation type" - which is modelled with a code list 
including "grid", "vector", "text table", etc. - see:

https://geo-ide.noaa.gov/wiki/index.php?title=ISO_19115_and_19115-2_CodeList_Dictionaries#MD_SpatialRepresentationTypeCode

In any case, GeoDCAT-AP models this information by using 
adms:representationTechnique + URIs corresponding to the items in the 
ISO 19115 code list.

 > Coordinate Reference System(s)

I've already mentioned the approach used in GeoDCAT-AP:

https://lists.w3.org/Archives/Public/public-sdw-wg/2016May/0072.html

The "link" between data and the relevant CRS(s) is made with 
dct:conformsTo - which is also in line with the use of such property in 
DQV to express conformance with a "standard".

 > spatial resolution

As I said in another mail [1], DQV may offer a solution to this:

https://www.w3.org/TR/vocab-dqv/#ExpressDatasetAccuracyPrecision

The examples cover spatial resolution expressed as horizontal ground 
distance, equivalent scale, angular distance (which is how spatial 
resolution is expressed in ISO 19115 - we just miss an example on 
vertical distance).


About making "spatial *meta*data indexable", is this going under BP1 as 
well? I think we have already good examples to include, also showing how 
this is a feature that can be (more or less) easily integrated in 
existing geo catalogue services and tools.

On this specific topic, I take the opportunity to mention that we 
started a mapping exercise between DCAT-AP + GeoDCAT-AP and Schema.org:

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

One of the preliminary results of this work is: do we really need to map 
everything? Besides the fact that Schema.org does not include terms to 
model all what is in DCAT-AP / GeoDCAT-AP, the use cases addressed by 
these metadata schemas are different. So, the question is: what is 
really needed to be mapped to Schema.org to enable Web indexing and 
discoverability?

I think this is a general design issue about enabling the re-use of 
spatial data (not only metadata), that, in my understanding, was shown 
pretty clearly in the Geonovum testbed, where only a "simplified" 
version of spatial data and metadata is represented via Schema.org.

Cheers,

Andrea

----
[1]https://lists.w3.org/Archives/Public/public-sdw-wg/2016Jul/0164.html


On 26/07/2016 14:47, Linda van den Brink wrote:
> Hi all,
>
>
>
> Finally, some progress. I’ve begun restructuring the Best Practices
> document based on the structure of the DWBP (same grouping and ordering
> of BPs). I shuffled all the BPs around to the best of my ability based
> on discussions we had in various places. I may have missed some insights
> because I find it difficult to keep track of all the mailing list
> discussions sometimes, so comments are more than welcome.  I’ve not
> started merging/consolidating BPs yet, but will do if appropriate. I’m
> working on them one by one, now.
>
>
>
> http://w3c.github.io/sdw/bp/
>
>
>
> In particular, I welcome more detailed comments on the section in the BP
> on spatial metadata. http://w3c.github.io/sdw/bp/#bp-metadata
>
>
>
> I’ve got three BPs in that section at the moment.
>
>
>
> The first one is about spatial coverage and other spatial descriptive
> metadata. Getting there, but needs examples at least.
>
>
>
> The second is about CRS – there have been comments on this in the past
> as well as recent discussion, which I’ve tried to capture without making
> the section overly long or complex. Please review!
>
>
>
> The third is on making the entities within a spatial dataset indexable
> (it was SDWBP25 in the FPWD). Even though this is not really a spatial
> but a general issue I’ve retained it for now, because it’s useful
> information and not detailed in DWBP. And even though it’s not clearly
> about metadata (at least not on dataset level), this section seems the
> best fit for it. Also, this BP needs examples and can probably be improved.
>
>
>
> Your thoughts are appreciated!
>
>
>
> Linda
>
>
>

-- 
Andrea Perego, Ph.D.
Scientific / Technical Project Officer
European Commission DG JRC
Directorate B - Growth and Innovation
Unit B6 - Digital Economy
Via E. Fermi, 2749 - TP 262
21027 Ispra VA, Italy

https://ec.europa.eu/jrc/
Received on Tuesday, 26 July 2016 14:55:53 UTC

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