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Re: Some comments on the spatial ontology (sdwgeo)

From: Frans Knibbe <frans.knibbe@geodan.nl>
Date: Mon, 26 Sep 2016 13:37:08 +0200
Message-ID: <CAFVDz43p96rJEKXEM58vLU6gM_hVe2Cx87N066y8+koHsuteqw@mail.gmail.com>
To: Simon Cox <Simon.Cox@csiro.au>
Cc: Joshua Lieberman <jlieberman@tumblingwalls.com>, SDW WG Public List <public-sdw-wg@w3.org>
Thank you Simon. It is good to have that, especially the Linked Data
representation. I have added the information to the reference section of
the spatial ontology wiki
<https://www.w3.org/2015/spatial/wiki/Further_development_of_GeoSPARQL#Relevant_standards>,
so we don't forget.

Greetings,
Frans

On 26 September 2016 at 02:08, <Simon.Cox@csiro.au> wrote:

> Ø  It refers to ISO 19109, but that definition is not something everyone
> can look up.
>
>
>
> As mentioned a couple of times earlier, the full glossary of definitions
> from ISO 19100-series standards are available at [1] and I also put up a
> provisional linked-data representation at [2] (will be superseded by an
> official one soon – I’m assisting in its preparation.)
>
>
>
> I strongly suggest that we make use of and reference to this glossary,
> since it is already used by all those agencies that endorse the ISO
> standards. The definitions may not be exactly what you would write, but it
> would be a serious mistake for the SDWWG to adopt definitions that clashed
> with the ISO ones.
>
>
>
> [1] http://www.isotc211.org/Terminology.htm
>
> [2] http://registry.it.csiro.au/sandbox/iso-tc211/terms
>
>
>
> *From:* Frans Knibbe [mailto:frans.knibbe@geodan.nl]
> *Sent:* Saturday, 24 September 2016 12:13 AM
> *To:* Joshua Lieberman <jlieberman@tumblingwalls.com>
> *Cc:* SDW WG Public List <public-sdw-wg@w3.org>
> *Subject:* Some comments on the spatial ontology (sdwgeo)
>
>
>
> Hello Josh,
>
>
>
> Many times during the F2F meeting in Lisbon the idea that work on an
> agreed spatial ontology is very important was confirmed for me. So I had a
> look at the ontology in WebProtégé
> <http://webprotege.stanford.edu/#Edit:projectId=fa09f9df-1078-4c17-a16c-ae83695ff431>
> in its current state. You wrote that comments are welcome. I thought a
> message like this would be the best way to share such comments,
> although WebProtégé has its own comment system - it could be that comments
> in WebProtégé go unnoticed and besides that all decision making should be
> publicly recorded for eternity.
>
>
>
> So below are some comments and questions. Please excuse me for any stupid
> comments, I am not an ontologist and there are probably a lot of things I
> misunderstand.
>
>
>
> And I hope that more people can find the time to look at this crucial
> piece of work.
>
>    1. Most importantly: Thank you for setting up the ontology!
>    2. Earlier I asked about starting with the GeoSPARQL ontology and work
>    from there. You answered that is not practical because WebProtégé does not
>    seem to support refactoring. Still, it seems to me that the base classes
>    and properties defined in GeoSPARQL 1.0.1 (gspql:geometry,
>    gspql:SpatialObject and gspql:Feature) should be in the new ontology
>    somewhere, if only for ensuring backward compatibility.
>    3. I wondered if topology should be included in the ontology (see my
>    earlier message to the list
>    <https://lists.w3.org/Archives/Public/public-sdw-wg/2016Sep/0190.html>),
>    but I noticed it's already in there (in the TopoModel class). I am happy to
>    see that.
>    4. SpatialThing is an important class, but its definition is not
>    clear. It refers to ISO 19109, but that definition is not something
>    everyone can look up. How about definitions like "Something that has some
>    kind of spatial presence", or the current definition in the BP document,
>    taken from the Basic Geo vocabulary: "Anything with spatial extent, i.e.
>    size, shape, or position. e.g. people, places, bowling balls, as well as
>    abstract regions like cubes."
>    5. Continuing the point above, can SpatialThing be defined as some
>    sort of equivalent of geo:SpatialThing?
>    6. I assume the intention of the SpatialModel class is that it can
>    represent a model of a SpatialThing. Shouldn't it say so in its
>    definition/comment?
>    7. If Extent is not defined as it usually is understood (an indication
>    of the space a spatial thing occupies), but as a synonym of dimensionality,
>    then why is Extent a subclass of SpatialModel?
>    8. If Extent is not meant to be used to indicate the space a spatial
>    thing occupies (e.g. a minimal bounding rectangle), then which part of the
>    ontology is meant for that?
>    9. In a general view of spatial relations there are three types:
>    topological relations (e.g. within, crosses), distance relations (e.g. at,
>    near to, far from)  and directional relations (e.g. north of, upstairs
>    from, behind). Would it make sense to define these types as subproperties
>    of spatialRelation, and let the current set of subproperties be
>    subproperties of e.g. topologicalRelation?
>    10. In Lisbon we had some discussion about the computability of
>    spatial relationships, specifically topological relationships. In my view,
>    both SpatialThings and Geometries can have spatial relationships. In the
>    first case, they can be used as assertions, in the second case they are
>    computable. If this view makes sense, is it useful to define two sets of
>    spatialRelations, one for spatial things and one for geometries?
>    11. Another suggestion made in Lisbon: could we regard the
>    spatialRelation 'equals' as meeting the requirement to express subject
>    equality
>    <http://w3c.github.io/sdw/UseCases/SDWUseCasesAndRequirements.html#SubjectEquality>
>    ?
>    12. I see that the property hasSerialization has three subproperties:
>    asGML, asJSON and asWKT. But GML, JSON and WKT have very different levels
>    of expressiveness. For example, WKT has no way of expressing CRS or
>    resolution. JSON, on the ohter hand, is a very general format so it is not
>    so clear what the serialization would look like. Or did you mean GeoJSON?
>    13. Is there an entity in the ontology that can be used for expressing
>    the array of coordinates that can be used to define a geometry?
>    14. I find it quite hard to see how the parts of the ontology are
>    related. I think understanding the use of the ontology would be helped a
>    lot with some examples (resource descriptions in RDF). I would like to try
>    to make some examples, but what would be a good place for that? A new wiki
>    page? Or is it better to start with a proper HTML document in GitHub that
>    explains how to use the ontology, something that can be turned into a more
>    or less official document?
>    15. Can other people edit the ontology? Perhaps others can contribute
>    resource descriptions (labels and comments in different languages).
>    16. Why is LinearReference a separate class? Isn't it the same as a 2D
>    CRS?
>    17. I see a property 'resolution' has been defined. But it does not
>    seem to be related to other entities. Will it be a property of SpatialModel?
>    18. Can the ontology be related to the Location Core Vocabulary
>    <https://www.w3.org/ns/locn>? That would give the opportunity to refer
>    to SpatialThings by address or toponym. For example, could dcterms:Location
>    be defined as a equivalent class or subclass of SpatialThing?
>    19. Can the range of spatialDimension be specified as one the integers
>    1, 2 or 3?
>
>
>
> This is what I've come up with now. Probably questions will disappear or
> form when understanding increases. Having a set of examples of how the
> ontology can be used would probably help a lot for that understanding, and
> I think that working of implementation examples from our own fields of work
> could be a fun & fruitful group activity.
>
>
>
> Greetings,
>
> Frans
>
Received on Monday, 26 September 2016 11:37:40 UTC

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