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

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.

Clemens



On 1. Juni 2016 at 03:37:53, Joshua Lieberman (jlieberman@tumblingwalls.com<mailto: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>> 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>> wrote:
I’m questioning whether that is a good idea.

[cid:A95347D1-D499-402E-AC40-7343F76A880F]


On May 31, 2016, at 7:43 PM, simon.cox@csiro.au<mailto:simon.cox@csiro.au> wrote:

In GeoSPARQL SpatialObject is superclass of geometry and spatial feature.

-----Original Message-----
From: Joshua Lieberman [mailto: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>>
Cc: andrea.perego@jrc.ec.europa.eu<mailto:andrea.perego@jrc.ec.europa.eu>; l.vandenbrink@geonovum.nl<mailto:l.vandenbrink@geonovum.nl>; frans.knibbe@geodan.nl<mailto:frans.knibbe@geodan.nl>; public-sdw-wg@w3.org<mailto: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> 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
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________________________________________
From: Joshua Lieberman <jlieberman@tumblingwalls.com<mailto: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>)
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>> 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


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