- From: Matthew Perry <matthew.perry@oracle.com>
- Date: Tue, 25 Apr 2017 07:53:21 -0400
- To: public-sdw-wg@w3.org
- Message-ID: <af7ecbc5-2f84-81b9-ad1b-43727c1774b9@oracle.com>
That looks correct to me as well. Thanks, Matt On 4/25/2017 12:29 AM, Joshua Lieberman wrote: > Yes, I think. > >> On Apr 25, 2017, at 12:19 AM, <Simon.Cox@csiro.au >> <mailto:Simon.Cox@csiro.au>> <Simon.Cox@csiro.au >> <mailto:Simon.Cox@csiro.au>> wrote: >> >> Ø... and reaffirm that _we_ see Feature (SpatialThing) as disjoint >> from geometry, but that this might be at odds with some people's >> interpretations. As Josh says: "we can’t really say there is a >> mapping from W3C Basic Geo to/from anything based on 19109." >> We need to be very clear here: >> geosparql:SpatialObject includes both features and geometries >> – they are disjoint subclasses >> w3cgeo:SpatialThing is superclass of w3cgeo:Point, but >> (OWA) potentially also has a class of features as another subclass >> (disjoint from Point) – so this could all be OK and consistent (but >> we mustn’t credit w3cgeo as having been the result of much deep thought). >> So where does bp:SpatialThing fit in? Looks to me like the key thing >> is to point out that it is **not** the same as w3cgeo:SpatialThing, >> because the latter includes geometries. But it **is** the same as >> geosparql:Feature, which is disjoint from Geometry. >> Simon** >> *From:*Clemens Portele [mailto:portele@interactive-instruments.de] >> *Sent:*Tuesday, 25 April, 2017 01:27 >> *To:*Jeremy Tandy <jeremy.tandy@gmail.com >> <mailto:jeremy.tandy@gmail.com>> >> *Cc:*Josh Lieberman <jlieberman@tumblingwalls.com >> <mailto:jlieberman@tumblingwalls.com>>; Cox, Simon (L&W, Clayton) >> <Simon.Cox@csiro.au <mailto:Simon.Cox@csiro.au>>; Rob Atkinson >> <rob@metalinkage.com.au <mailto:rob@metalinkage.com.au>>; Andreas >> Harth <harth@kit.edu <mailto:harth@kit.edu>>; public-sdw-wg@w3.org >> <mailto:public-sdw-wg@w3.org> >> *Subject:*Re: SpatialThing and feature (again) >> Hi Jeremy, >> I think we should add a green note in chapter 5 to explain how the >> "anything with spatial extent" definition is consistent with features >> like a "home loan" in a spatial dataset as it is not obvious. >> Clemens >> >> On 21. Apr 2017, at 17:33, Jeremy Tandy <jeremy.tandy@gmail.com >> <mailto:jeremy.tandy@gmail.com>> wrote: >> Hi all- >> I've spent more than a few minutes parsing through the email chain. >> 1/ Clemens' summary (from mid way though) suggests that (a) ISO >> 19109 Feature is [also] a geosparql:Feature, (b) these may or may >> not have attached geometry properties >> 2/ Andrea suggests that "only [those] ISO 19109 Features [with >> spatial extent] are Spatial Things according to the BP >> definition" - but Josh suggests we're using "spatial extent" as a >> shorthand for "real-world phenomena", and that "making the >> connection [between abstraction and real-world thing] formal and >> explicit is not necessary for Web purposes" >> So I'm seeing that there's no inconsistency to explain away. >> Please confirm that I've read this OK. Apologies if I've missed >> the point! >> And, talking of Points ... I see that there is potential for >> confusion regarding the "Feature/Geometry amalgam". >> We could insert a "green note" into the BP document identifying >> the potential for inconsistency - as defined in Andreas' example: >> > Because a w3cgeo:SpatialThing has lat/lon, some people might >> equate a w3cgeo:SpatialThing with a geosparql:Geometry. >> > >> > Because the w3cgeo:SpatialThing is an instance of foaf:Person, >> some other people find it natural to equate the >> w3cgeo:SpatialThing with a geosparql:Feature. >> > >> > Based on data from different source we now have an >> inconsistency, because the w3cgeo:SpatialThing is an instance of >> both geosparql:Feature and geosparql:Geometry, which are defined >> as disjoint. >> ... and reaffirm that _we_ see Feature (SpatialThing) as disjoint >> from geometry, but that this might be at odds with some people's >> interpretations. As Josh says: "we can’t really say there is a >> mapping from W3C Basic Geo to/from anything based on 19109." >> Am I summarising correctly? >> Thanks, Jeremy >> On Fri, 21 Apr 2017 at 15:33 Joshua Lieberman >> <jlieberman@tumblingwalls.com >> <mailto:jlieberman@tumblingwalls.com>> wrote: >> >> Ah, I had thought that the domains of geo:lat and geo:lon >> were geo:Point, since that is what is generally referred to >> in narrative. If a resource carrying the lat/lon properties >> implies that it is a SpatialThing, not only the Point >> subclass, adding the properties doesn’t resolve any feature / >> geometry ambiguity. Your equivalences are certainly possible, >> but geosparql doesn’t / shouldn’t support adding direct >> positions to features, so entailing something with geo:lat >> and geo:lon as geosparql:SpatialObject rather than >> geosparql:Geometry doesn’t really work. And if we can’t >> derive that use of geo:lat and geo:lon imply both a feature >> and a geometry, than Andrea is correct that we can’t really >> say there is a mapping from W3C Basic Geo to/from anything >> based on 19109. That may be unfortunate. >> —Josh >> >> On Apr 20, 2017, at 8:38 PM,simon.cox@csiro.au >> <mailto:simon.cox@csiro.au>wrote: >> >> Hold on a moment folk – does this problem really exist? >> I’m looking athttp://www.w3.org/2003/01/geo/wgs84_pos# >> <http://www.w3.org/2003/01/geo/wgs84_pos>which is the >> RDF/XML serialization of W3C Basic Geo. >> Here’s the key axioms. >> geo:lat rdfs:domain geo:SpatialThing . >> geo:long rdfs:domain geo:SpatialThing . >> geo:Point rdfs:subClassOf geo:SpatialThing . >> >> And >> fromhttp://schemas.opengis.net/geosparql/1.0/geosparql_vocab_all.rdf >> since >> geosparql:Geometry rdfs:subClassOf geosparql:SpatialObject . >> then it looks to me like >> geo:SpatialThing owl:equivalentClass >> geosparql:SpatialObject . >> geo:Point rdfs:subClassOf geosparql:Geometry . >> and there is no inconsistency. Appearance of geo:lat and >> geo:long properties only entails that it is a >> geosparql:SpatialObject, so can be either a Feature or a >> Geometry. >> Am I missing something? >> Simon >> *From:*Rob Atkinson [mailto:rob@metalinkage.com.au] >> *Sent:*Thursday, 20 April, 2017 06:24 >> *To:*Joshua Lieberman <jlieberman@tumblingwalls.com >> <mailto:jlieberman@tumblingwalls.com>>; Andreas Harth >> <harth@kit.edu <mailto:harth@kit.edu>> >> *Cc:*public-sdw-wg@w3.org <mailto:public-sdw-wg@w3.org> >> *Subject:*Re: SpatialThing and feature (again) >> This could also be resolved by thinking of geo:long as a >> property that can entail a geometry property of the >> feature - maybe its even a geometry property in the same >> way that a 2D point is a partial representation of a 3D >> location? >> Rob >> On Thu, 20 Apr 2017 at 02:38 Joshua Lieberman >> <jlieberman@tumblingwalls.com >> <mailto:jlieberman@tumblingwalls.com>> wrote: >> >> Andreas, >> >> It may not be worth delving too deeply into this... >> >> W3C Basic Geo defines SpatialThing and then >> subclasses it to Point carrying the lat and long >> properties. No one defines their own SpatialThings, >> they simply add geo:lat and geo:long properties to >> some resource X to turn it into “also a Point”, in >> other words “also a geometry”. This implies for most >> users but does not actually assert that resource X is >> both a feature and a geometry. One could form a >> subclass of geo:SpatialThing that was actually >> disjoint with geo:Point or other geometry, which >> would then align more-or-less with iso >> geosparql:Feature, hence the assertion that some >> geo:SpatialThings are geosparql:Features. This is >> largely hypothetical. >> >> There is a similar property in GeoRSS, the point(pos) >> property, but this doesn’t try to create one >> feature-geometry amalgam. It’s simply a shortcut for >> a longer expression that identifies some resource as >> a _Feature with a “where" object property connecting >> to a Point geometry resource. >> >> It might be most accurate to say that your example of >> using W3C Basic Geo to represent feature and geometry >> in the “style” of geosparql is actually the longhand >> of what people are trying to do when they do use >> geo:lat and geo:long, identifying a resource as a >> real world feature and giving it a closely allied >> point geometry. >> >> —Josh >> >> > On Apr 19, 2017, at 11:54 AM, Andreas Harth >> <harth@kit.edu <mailto:harth@kit.edu>> wrote: >> > >> > Hi, >> > >> > On 04/19/17 13:29, Joshua Lieberman wrote: >> >> My understanding based on the limited >> documentation is that w3cgeo:SpatialThing covers both >> features and models such as geometries, so >> > >> > that's my understanding too. With the W3C WGS84 >> vocabulary you can write: >> > >> > @prefix geo: >> <http://www.w3.org/2003/01/geo/wgs84_pos# >> <http://www.w3.org/2003/01/geo/wgs84_pos>> . >> > @prefix : <#> . >> > >> > :bob a geo:SpatialThing ; geo:lat "52.5196143" ; >> geo:long "13.4065603" . >> > >> > So the resource with the URI :bob is both the >> "feature" and the "geometry". >> > >> > In other representations (NeoGeo, GeoSPARQL), you >> would identify two separate >> > resources: >> > >> > @prefix geo: >> <http://www.w3.org/2003/01/geo/wgs84_pos# >> <http://www.w3.org/2003/01/geo/wgs84_pos>> . >> > @prefix : <#> . >> > >> > :bob a :Feature ; :geometry _:bnode . >> > _:bnode a :Geometry , geo:Point ; geo:lat >> "52.5196143" ; geo:long "13.4065603" . >> > >> > The URI :bob now represents the "feature" resource, >> and the blank node _:bnode >> > represents the "geometry" resource. >> > >> > I wouldn't know how to write OWL axioms to map the >> two modeling choices though. >> > >> > Best regards, >> > Andreas. >> > >> > >> >
Received on Tuesday, 25 April 2017 11:54:06 UTC