Re: Agenda for Best Practice sub-group, 14:00UTC 1-June-2016

So are we saying that a Feature is the same as a Spatial Object?

It probably depends on your background which of those names is most
evocative - obviously both are, in themselves, open to interpretation.

To me 'feature' makes me think of maps, whereas 'spatial object' (while not
necessarily the best name ever - 'spatial thing' while also very vague is
perhaps slightly better because of all the software and information
modelling uses of 'object') makes me think of something I could see or walk
round or hit with a hammer.

Whatever we call it, I think we should be talking about things you can see
and walk round.



On 3 June 2016 at 13:18, Rob Atkinson <rob@metalinkage.com.au> wrote:

>
> "(something like: things that have some kind of spatial presence" ... well
> - thats what a feature is, and it is at least defined somewhere - so surely
> we drop the more ambiguous term "spatial object" whose existence is a
> modelling artefact, not a real world need.  To me "spatial object" is too
> easily confused with either a feature or a geometry
>
> Feature and geometry both have real-world analogues - if we really need
> something like "spatial object" to support some logic then perhaps we can
> start off by defining why we need, and then debate a suitable name.
>
> rob
>
>
> On Fri, 3 Jun 2016 at 19:59 Linda van den Brink <l.vandenbrink@geonovum.nl>
> wrote:
>
>> Hi all,
>>
>>
>>
>> +1 That’s exactly what I was thinking this morning when I read this
>> thread. Without being able to put into words why I’m thinking this, as of
>> yet…
>>
>>
>>
>> Linda
>>
>>
>>
>> *Van:* Frans Knibbe [mailto:frans.knibbe@geodan.nl]
>> *Verzonden:* vrijdag 3 juni 2016 11:39
>> *Aan:* Joshua Lieberman; SDW WG Public List; Simon Cox; matthew perry
>> *Onderwerp:* Re: Agenda for Best Practice sub-group, 14:00UTC 1-June-2016
>>
>>
>>
>> Hello all,
>>
>>
>>
>> GeoSPARQL defines three core entities: Feature, SpatialObject and
>> Geometry. However, in my (possibly too naive) view we only need two core
>> concepts:
>>
>>    1. spatial things: (something like: things that have some kind of
>>    spatial presence, and that can have spatial relationships)
>>    2. geometry: (something like: an ordered set of n-dimensional points,
>>    can be used to model the spatial presence of a spatial thing)
>>
>> Is there really a need to have a third concept (Feature)? If the world
>> could manage with two core concepts, that would be preferable, wouldn't it?
>>
>>
>>
>> Regards,
>>
>> Frans
>>
>>
>>
>>
>>
>> 2016-06-02 17:54 GMT+02:00 Joshua Lieberman <jlieberman@tumblingwalls.com
>> >:
>>
>> Simon, Matt, et al,
>>
>>
>>
>> I’m struggling a bit with this right now. Theoretically, spatial
>> relationships can only be computed / tested between geometries. Features
>> are discerned Things in the world that don’t necessarily have spatial
>> representations and so it makes sense that they are not themselves spatial
>> objects. Features and geometries can be disjoint whether or not feature is
>> a spatial object, but it gets awkward to make features disjoint from all
>> other spatial objects (e.g. address, geographic name, region) if features
>> are also spatial objects.
>>
>>
>>
>> [Topological relationship creation also requires topological elements,
>> although there is a question in my mind whether those elements are directly
>> spatial spatial objects or an algebraic reduction of certain spatial
>> relationships. It is related to the dimensionality issue, since topo
>> elements are distinguished by dimension. There is also a question in my
>> mind whether features and topo elements have to be disjoint as features and
>> geometries are or whether a road centerline can also be a topo edge.]
>>
>>
>>
>> Conceptually, though, one would like to express relationships between
>> features themselves. For example, I would (very much) like to assert /
>> infer / query that one hydrological catchment (a portion of a landscape) is
>> inside of another one, not that one possible geometric representation of
>> one catchment is interior to one possible geometric representation of the
>> other catchment.
>>
>>
>>
>> It seems that we can relate the two with a property chain, so that a
>> relationship between geometries implies a relationship between the
>> features, but does it make sense to use the same relationships for both if
>> feature is not a spatial object? Alternatively, we could create “feature
>> relationships”, e.g. gfInside for inside:
>>
>>
>>
>> SubObjectPropertyOf(
>>
>>    ObjectPropertyChain( :hasGeometry ehInsite [ owl:inverseOf :hasParent]
>> )
>>
>>    :gfInside
>>
>>  )
>>
>>
>>
>> In the end, I think we want to enable people to form the assertions that
>> make sense to them, but also maximize the possibilities for query and
>> inference. So I’m inclined towards creating feature-specific relations,
>> some of which can be inferred from spatial object relations. Thoughts?
>>
>>
>>
>> —Josh
>>
>>
>>
>> On Jun 1, 2016, at 9:49 PM, simon.cox@csiro.au wrote:
>>
>>
>>
>> “Regional Shape” and “Regional Area” are both a bit iffy:
>>
>> “area” and “region” are approximate synonyms;
>>
>> “shape” sounds like just the outline.
>>
>>
>>
>> *From:* Joshua Lieberman [mailto:jlieberman@tumblingwalls.com
>> <jlieberman@tumblingwalls.com>]
>> *Sent:* Wednesday, 1 June 2016 11:23 PM
>> *To:* matthew perry <matthew.perry@oracle.com>
>> *Cc:* public-sdw-wg@w3.org
>> *Subject:* Re: Agenda for Best Practice sub-group, 14:00UTC 1-June-2016
>>
>>
>>
>> Matt,
>>
>>
>>
>> Thanks for giving us a perspective on the current form of GeoSPARQL. Your
>> point about qualitative relations is well taken. This was discussed fairly
>> extensively last summer at the Vespucci Institute, but we discovered that
>> most of the relations of interest still require at least some spatial
>> characterization of the feature, at least a regional dimensionality. For
>> example, New York inside of United States presumes that the U.S. is at
>> least a 2-dimensional region. The relation “along” requires that the object
>> feature have an elongation in at least one dimension.
>>
>>
>>
>> I have been thinking that we should add a subclass of SpatialObject,
>> RS_Object (Regional Shape) that provides this regionality to support
>> qualitative reasoning. Then we could keep Feature out of SpatialObject and
>> still do qualitative reasoning.
>>
>>
>>
>> <image001.png>
>>
>>
>>
>> Josh
>>
>>
>>
>> On Jun 1, 2016, at 8:43 AM, matthew perry <matthew.perry@oracle.com>
>> wrote:
>>
>>
>>
>> Hi everyone,
>>
>> The Feature subClassOf SpatialObject does seem a bit awkward in
>> retrospect. The main idea was that for qualitative spatial reasoning, we
>> don't need quantitative geometries. It should be possible to express
>> topological relations between features directly (e.g., New York inside
>> United States), so we defined SpatialObject as the class of things that can
>> have topological relations, and Feature and Geometry are disjoint
>> subClasses of SpatialObject.
>>
>> Thanks,
>> Matt
>>
>>
>>
>> On 6/1/2016 4:58 AM, Clemens Portele wrote:
>>
>> Hm, yes, good question. I did not remember that we made geo:Feature a
>> geo:SpatialObject in the GeoSPARQL development. I agree with you, from the
>> definitions this seems wrong. Perhaps that could be rediscussed, if there
>> is a GeoSPARQL revision.
>>
>>
>>
>> Clemens
>>
>>
>>
>> On 1. Juni 2016 at 10:38:24, Andrea Perego (
>> andrea.perego@jrc.ec.europa.eu) wrote:
>>
>> Hi, Clemens.
>>
>> On 01/06/2016 8:26, Clemens Portele wrote:
>> > If we use 19107 as the basis, a TP_Object is a SpatialObject, too.
>> >
>> > This is the definition of "topological object" (the TP_Object):
>> > "spatial object representing spatial characteristics that are invariant
>> > under continuous transformations".
>> >
>> > The definition of "geometric object" (the GM_Object) is: "spatial
>> object
>> > representing a geometric set" where geometric set is "a set of points".
>> >
>> > GeoSPARQL is consistent with this, geo:Geometry is a sub-class of
>> > geo:SpatialObject. If we would define xyz:Topology it should be a
>> > sub-class of geoSpatialObject, too.
>>
>> What is unclear to me is why, in GeoSPARQL, feature is made a subclass
>> of spatial object.
>>
>> Putting together the relevant ISO definitions:
>> - feature: "abstraction of real-world phenomena" (ISO 19101, 19107,
>> 19109, 19156)
>> - spatial object: "object used for representing a spatial characteristic
>> of a feature" (ISO 19107)
>> - geometry (geometric object): "spatial object representing a geometric
>> set" (ISO 19107)
>>
>> Based on them, a feature is not a spatial object - or I'm missing
>> something?
>>
>> Andrea
>>
>>
>> > Clemens
>> >
>> >
>> > On 1. Juni 2016 at 03:37:53, Joshua Lieberman
>> > (jlieberman@tumblingwalls.com <mailto:jlieberman@tumblingwalls.com>
>> <jlieberman@tumblingwalls.com>) wrote:
>> >
>> >> Yes, a GM_object instance is generally a geometry, but there can be
>> >> other spatial objects such as linear references, addresses,
>> >> placenames, etc. I’m pondering now whether TP_Object should also be a
>> >> subclass of SpatialObject, but I think it too is a form of spatial
>> model.
>> >>
>> >> “Object” is vague, but possibly less confusing than “model” or
>> >> “representation”. The confusion may be a fundamental property of the
>> >> GFM, because one first models the worlds as features, then models the
>> >> features in turn as spatial objects. Making both feature and geometry
>> >> disjoint subclasses of spatial object in GeoSPARQL means, I think,
>> >> that SpatialObject really can’t mean anything except a step of removal
>> >> from owl:Thing.
>> >>
>> >> Josh
>> >>
>> >>> On May 31, 2016, at 9:11 PM, Rob Atkinson <rob@metalinkage.com.au
>> >>> <mailto:rob@metalinkage.com.au> <rob@metalinkage.com.au>> wrote:
>> >>>
>> >>> it all depends what you mean :-)
>> >>>
>> >>> I though a GM_object was specifically a geometry. As such it is
>> >>> independent of any real world thing - but it can be used as a
>> >>> property of a real world thing to define a spatial characteristic.
>> >>>
>> >>> as such I would say GM_Object and (real world thing) are disjoint.
>> >>>
>> >>> What I dont really understand is what a Spatial Object is, except it
>> >>> seems to declare that Egenhofer and other spatial operations can be
>> >>> supported on either GM_Object or GF_Feature.{geomproperty}. One
>> >>> wonders if a more elegant way of declaring this was possible without
>> >>> introducing a very strange abstract notion (and the confusion here I
>> >>> think is the evidence for the strangeness)
>> >>>
>> >>> OTOH running with the geoSPARQL as-is makes sense unless its provably
>> >>> broken in terms of the inferences it allows, so I'll just get over my
>> >>> distaste of incompatible naming vs. intent.
>> >>>
>> >>> Rob
>> >>>
>> >>>
>> >>>
>> >>>
>> >>> On Wed, 1 Jun 2016 at 09:58 Joshua Lieberman
>> >>> <jlieberman@tumblingwalls.com <mailto:jlieberman@tumblingwalls.com>
>> <jlieberman@tumblingwalls.com>>
>> >>> wrote:
>> >>>
>> >>> I’m questioning whether that is a good idea.
>> >>>
>> >>>
>> >>>
>> >>>> On May 31, 2016, at 7:43 PM, simon.cox@csiro.au
>> >>>> <mailto:simon.cox@csiro.au> <simon.cox@csiro.au> wrote:
>> >>>>
>> >>>> In GeoSPARQL SpatialObject is superclass of geometry and spatial
>> >>>> feature.
>> >>>>
>> >>>> -----Original Message-----
>> >>>> From: Joshua Lieberman [mailto:jlieberman@tumblingwalls.com
>> <jlieberman@tumblingwalls.com>]
>> >>>> Sent: Wednesday, 1 June 2016 9:39 AM
>> >>>> To: Cox, Simon (L&W, Clayton) <Simon.Cox@csiro.au
>> >>>> <mailto:Simon.Cox@csiro.au> <Simon.Cox@csiro.au>>
>> >>>> Cc: andrea.perego@jrc.ec.europa.eu
>> >>>> <mailto:andrea.perego@jrc.ec.europa.eu>
>> <andrea.perego@jrc.ec.europa.eu>;
>> >>>> l.vandenbrink@geonovum.nl <mailto:l.vandenbrink@geonovum.nl>
>> <l.vandenbrink@geonovum.nl>;
>> >>>> frans.knibbe@geodan.nl <mailto:frans.knibbe@geodan.nl>
>> <frans.knibbe@geodan.nl>;
>> >>>> public-sdw-wg@w3.org <mailto:public-sdw-wg@w3.org>
>> <public-sdw-wg@w3.org>
>> >>>> Subject: Re: Agenda for Best Practice sub-group, 14:00UTC
>> >>>> 1-June-2016
>> >>>>
>> >>>> Can't SpatialObject be disjoint from GF_Feature? Maybe it's
>> >>>> really SpatialRepresentation. Unless we want to call it
>> >>>> TransfinitePointSet.
>> >>>>
>> >>>>> On May 31, 2016, at 6:20 PM, simon.cox@csiro.au
>> >>>>> <mailto:simon.cox@csiro.au> <simon.cox@csiro.au> wrote:
>> >>>>>
>> >>>>> That preserves the 'thing is not a subclass of geometry' axiom,
>> >>>>> but misses 'geometry is not a subclass of real-world-thing'.
>> >>>>> I don't see how to do that without a subclass of owl:Thing
>> >>>>> which is disjoint from GM_Object.
>> >>>>>
>> >>>>> Simon J D Cox
>> >>>>> Research Scientist
>> >>>>> Land and Water
>> >>>>> CSIRO
>> >>>>> E simon.cox@csiro.au <mailto:simon.cox@csiro.au>
>> <simon.cox@csiro.au> T +61 3 9545
>> >>>>> 2365 M +61 403 302 672
>> >>>>> Physical: Reception Central, Bayview Avenue, Clayton, Vic 3168
>> >>>>> Deliveries: Gate 3, Normanby Road, Clayton, Vic 3168
>> >>>>> Postal: Private Bag 10, Clayton South, Vic 3169
>> >>>>> people.csiro.au/C/S/Simon-Cox
>> >>>>> <http://people.csiro.au/C/S/Simon-Cox>
>> <http://people.csiro.au/C/S/Simon-Cox>
>> >>>>> orcid.org/0000-0002-3884-3420
>> >>>>> <http://orcid.org/0000-0002-3884-3420>
>> <http://orcid.org/0000-0002-3884-3420>
>> >>>>> researchgate.net/profile/Simon_Cox3
>> >>>>> <http://researchgate.net/profile/Simon_Cox3>
>> <http://researchgate.net/profile/Simon_Cox3>
>> >>>>>
>> >>>>> ________________________________________
>> >>>>> From: Joshua Lieberman <jlieberman@tumblingwalls.com
>> >>>>> <mailto:jlieberman@tumblingwalls.com>
>> <jlieberman@tumblingwalls.com>>
>> >>>>> Sent: Wednesday, 1 June 2016 7:12 AM
>> >>>>> To: Andrea Perego
>> >>>>> Cc: Linda van den Brink; Frans Knibbe; SDW WG
>> >>>>> (public-sdw-wg@w3.org <mailto:public-sdw-wg@w3.org>
>> <public-sdw-wg@w3.org>)
>> >>>>> Subject: Re: Agenda for Best Practice sub-group, 14:00UTC
>> >>>>> 1-June-2016
>> >>>>>
>> >>>>>> On May 31, 2016, at 10:01 AM, Andrea Perego
>> >>>>>> <andrea.perego@jrc.ec.europa.eu
>> >>>>>> <mailto:andrea.perego@jrc.ec.europa.eu>
>> <andrea.perego@jrc.ec.europa.eu>> wrote:
>> >>>>>>
>> >>>>>> Dear Linda, dear Frans, dear Josh,
>> >>>>>>
>> >>>>>> About the agenda item on "spatial ontology", I wonder whether
>> >>>>>> we can include here a clarification on the notions of spatial
>> >>>>>> object, feature and geometry in GeoSPARQL - in relation to
>> >>>>>> ISO, and to our discussion on real-world / spatial things.
>> >>>>>>
>> >>>>>> In particular:
>> >>>>>>
>> >>>>>> 1. In GeoSPARQL, feature and geometry are explicitly mapped to
>> >>>>>> the corresponding notions in the relevant ISO standards.
>> >>>>>> However, the definition of spatial object in GeoSPARQL doesn't
>> >>>>>> seem to match to the ISO one ("object used for representing a
>> >>>>>> spatial characteristic of a feature" - ISO 19107).
>> >>>>>
>> >>>>> Yes, it's questionable whether GF_Feature should be considered
>> >>>>> a "Spatial Object". In ISO 19109, it's a real-world target of
>> >>>>> discourse, that can have properties, including one or more
>> >>>>> geometric model representations. I'm tending towards making
>> >>>>> GF_Feature an owl:Thing, and leaving GM_Object as a SpatialObject.
>> >>>>>>
>> >>>>>> 2. What in GeoSPARQL corresponds to real-world / spatial things?
>> >>>>>>
>> >>>>>> Thanks
>> >>>>>>
>> >>>>>> Andrea
>> >>>>>>
>> >>>>>>
>> >>>>>> On 30/05/2016 10:22, Linda van den Brink wrote:
>> >>>>>>> Hi all,
>> >>>>>>>
>> >>>>>>>
>> >>>>>>>
>> >>>>>>> The Best Practice sub-group telecon agenda is at
>> >>>>>>> https://www.w3.org/2015/spatial/wiki/Meetings:BP-Telecon20160601
>> .
>> >>>>>>>
>> >>>>>>>
>> >>>>>>>
>> >>>>>>> Main agenda:
>> >>>>>>>
>> >>>>>>> * Progress of BP Narrative 2
>> >>>>>>>
>> >>>>>>> * Spatial ontology
>> >>>>>>>
>> >>>>>>>
>> >>>>>>>
>> >>>>>>> See you all on Wednesday! (else please advise any regrets).
>> >>>>>>>
>> >>>>>>>
>> >>>>>>>
>> >>>>>>> Linda
>> >>>>>>>
>> >>>>>>
>> >>>>>> --
>> >>>>>> 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/
>> >>>>>>
>> >>>>>>
>> >>>>>
>> >>>>>
>> >>>>>
>> >>>>
>> >>>>
>> >>>>
>> >>>>
>> >>>
>> >>> <SpatialObject.png><SpatialObject.png>
>> >>
>>
>> --
>> 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/
>>
>>
>>
>>
>>
>>
>>
>>
>>
>