- From: Rob Atkinson <rob@metalinkage.com.au>
- Date: Tue, 28 Feb 2017 19:59:14 +0000
- To: janowicz@ucsb.edu, Rob Atkinson <rob@metalinkage.com.au>, Maxime Lefrançois <maxime.lefrancois@emse.fr>, Simon.Cox@csiro.au, rgarcia@fi.upm.es
- Cc: public-sdw-wg@w3.org
- Message-ID: <CACfF9LxNuaZydKCPrEFU0tA1ZoozagAj-Orhz5wuNwiB0osmEg@mail.gmail.com>
Yeah its complicated... like healthcare apparently :-) This is why I wonder if its not best to work on the samplingFeaturePattern then provide a simple form where the FoI and the samplingFeature are the same. Soft-typing, where a property explicitly defines the type of the instance, is at least explicit about the types/instances issue. Hopefully it wont break existing SSN as its an optional method to add more information. On Wed, 1 Mar 2017 at 06:23 Krzysztof Janowicz <janowicz@ucsb.edu> wrote: > Hi, > > So, I thought about this for a while and I see 3 major problems (and a few > smaller issues). > > First, we would need to agree what exactly we want to model. Is this going > to be a relation between types or between types and individuals or between > individuals? > > Second, while I like the idea in general, do we want to introduce such > substantial changes to SSN (and potentially SOSA) so late in the process? I > am not sure what the answer to this should be, but I remember Kerry being > very concerned about even the smallest changes made to SSN. We would > certainly need to come up with implementation evidence. > > Third, I think the idea of using functional properties may lead to issues > for some features and the idea of samples, e.g., for the depth of > waterbodies, but I have to think about this a bit more. > > Cheers, > Jano > > > > > On 02/26/2017 02:05 PM, Rob Atkinson wrote: > > > It seems to me we have a few possible ways to manage links - all with pros > and cons. > > i would like to consider the Use Case where the digital representation of > a feature is in existence, and for simplicity let us assume its already > modelled (there is an OWL model) and its instances are dereferenceable > (Linked Data) and hence we only have to worry about referencing these, not > building the referencing mechanism. > > Such an instance may be generated through some official channel - such as > designation of a road as a public highway, registration of a land parcel, > official naming of a hydrologic unit for management purposes. > > in this case neither the instances nor the models are mutable - we can > make statements about them but we cant make those statements discoverable > by resolving the URIs - the classic Open World, AAA and non-unique naming > situations. > > In general - the ObservedProperty may not be referenced in the original > model or instance data - AAA - so maybe its always necessary to use SSN to > declare such properties - and the pattern proposed is necessary and > sufficient. > > AFAICT the main options before we get to the detailed options in [1] are: > 1) extend the model of the FoI - define our own graph and add statements > about the foi class that make it substitutable for sosa:FeatureOfInterest, > as per [1] > 2) leave the range of sosa:featureOfInterest open, and declare the type of > the foi in implementations (soft-typing) - requiring a new property foiType > 3) Always reference the FoI via an intermediate samplingFeature, which > must be defined using SSN semantics, and may reference the original > immutable FOI > 4) ? > > If we take this AAA case further, imagine a virtual observatory with data > from a million different citizen science projects, each having modelled its > FOI using project specific SSN as per the suggested pattern, and the data > all being available in the same graph (i.e. we could slice a repository by > FOI and get a massively varied number of observations about that feature). > We may have many different observation activities about the same property, > but done at different times, or using different methods to compare, > validate etc. > > The questions I have are: > > - how safe are we to have many SSN models of FOI, some referencing the > same property, others declaring the same sampling method/sensor etc on a > different property using the Option1 pattern? > - is it worth focusing on the sampling pattern, with the SSN description > of the samplingFeature as basic practice, and have guidance for how this > collapses to simply describing properties of an externally defined > Feature? > > Maybe all is good, but I for one would like to see evidence of safety of > more than one SSN description within a graph. > > Rob > > [1] - > https://www.w3.org/2015/spatial/wiki/Link_between_FeatureOfInterest_and_xxxProperty > > > On Mon, 27 Feb 2017 at 00:45 Maxime Lefrançois <maxime.lefrancois@emse.fr> > wrote: > > Dear Rob, Raúl, Simon, > > Please find below some reactions to your mails. > (in this mail, sosa:hasProperty and ssn:hasProperty are used > interchangeably) > > > to Rob; > > Someone that defines a sub-class of FeatureOfInterest should also define > the properties applicable to that class as sub-properties of > sosa:hasProperty. This would make explicit the "substitution" you are > refering to. > > SEAS encourages this, plus we encourage to model sub-properties of > sosa:hasProperty as functional. > > As an example: > > seas:ElectricPowerSystem a owl:Class ; > rdfs:subClassOf ssn:FeatureOfInterest ... > > seas:consumedElectricPower a owl:ObjectProperty , owl:FunctionalProperty > ; > rdfs:subPropertyOf ssn:hasProperty ; > rdfs:domain seas:ElectricPowerSystem ... > > <fridge/1> a seas:ElectricPowerSystem ; > seas:consumedElectricPower <fridge/1/consumption> . > > > > to Raúl, > > I added a section "What is an instances of ssn:Property ?" to the wiki > page [1]. The intent is to compare the different ways that oldssn:Property > is defined versus how it's used. > > I am surprised to see that some datasets define instances of ssn:Property > that are not strongly bound to some feature of interest. Do you think this > still conforms with the definition of ssn:Property ? > > > > to Rob again, > > you mention sosa:featureOfInterestType, what is this link ? > > I don't remember precisely of all my modeling attempts to associate > multiple values to different properties, but I remember that I tried hard > with RDF QB. > 1. First proposal was similar to the one you suggest, i.e., have some > generic measure component seas:consumptionMeasure, and a dimension > component seas:featureOfInterest. If I remember well, some problem arise if > you want to describe the consumption of both foi A and foi B in the same > dataset. > 2. second attempt was to bind the feature of interest directly to the > component specification. I think this one worked better, but some of the > partners refused to use RDF Data Cube and wanted some simpler vocabulary to > associate different values to different properties, at once. > > In the end, our seas:hasOutput property (which will shortly be renamed > seas:hasResult to be aligned to the outcome of this group), is loosely > defined and can link to: > - a RDF qb:DataSet, > - one or more instances of seas:Evaluation [2] at once, > - one or more URIs that act as names of RDF graphs, > - ... > > This has proven to be very flexible and account for several use cases. > > > > > to Simon, > > I'm not very familiar to UML with metaclasses etc. Is it correct to say > that in the ISO 19109, > - ElectricPowerSystem would be modeled as a class, and an instance of the > metaclass FeatureType, > - ConsumedElectricPower would be modeled as a class, and an instance of > the metaclass PropertyType, > - ElectricPowerSystem would have carrierOfCharacteristics > ConsumedElectricPower, but potentially not only > - ConsumedElectricPower would have theFeatureType ElectricPowerSystem, > but potentially not only > - fridge1 would be an instance of ElectricPowerSystem, > - frige1consumption would be an instance of ConsumedElectricPower > > then what would be the property of fridge1 that points to > frige1consumption ? > > > If I attempt to align this model with SSN, then I would say that ISO 19109 > properties is better aligned to the ssn:hasProperty property than to the > ssn:Property class: > > "sub-properties of ssn:hasProperty are strongly bound with the sub-class > of ssn:FeatureOfInterest that they apply to (strongly bound here = their > domain is the sub-class of ssn:FeatureOfInterest). " > > > The changes that you pushed into ISO 19109:2015 are very interesting, > > (i) following this change, we should discourage SSN users to define the > domain of a ssh:hasProperty, but instead rely on local restrictions at > the level of the sub-class of ssn:FeatureOfInterest. > > i.e., if some FeatureType ElectricPowerSystem is the carrier of some > characteristics ConsumedElectricPower, then we could map this to SSN as > follows: > > seas:ElectricPowerSystem a owl:Class ; > rdfs:subClassOf ssn:FeatureOfInterest ; > rdfs:subClassOf [ > owl:onProperty seas:consumedElectricPower > owl:someValuesFrom owl:Thing ] . > > seas:consumedElectricPower a owl:ObjectProperty , owl:FunctionalProperty > ; > rdfs:subPropertyOf ssn:hasProperty ; > > > (ii) this is where the SEAS model diverges from ISO 19109: Properties are > assigned some value using class seas:Evaluation [2], which is not a > super-class of ssn:Observation. One or more evaluations may be used as some > command for an Actuation. One or more evaluation may be the result of a > seas:Observation, a seas:OptimizationExecution, or a seas:Forecast [3]. I > like the name "ValueAssignment" though and would have been tempted to use > it in place of "Evaluation". Unfortunately, this could bring some confusion > to the people that are familiar to ISO 19109. > > > Kind regards, > Maxime > > [1] - > https://www.w3.org/2015/spatial/wiki/Link_between_FeatureOfInterest_and_xxxProperty > [2] - https://w3id.org/seas/Evaluation > [3] - https://w3id.org/seas/OptimizationExecution > [4] - https://w3id.org/seas/Forecast > > Le sam. 25 févr. 2017 à 05:27, <Simon.Cox@csiro.au> <Simon.Cox@csiro.au> > a écrit : > > Whoops - attached the wrong part of Figure 5 - here's the bit that matters. > > -----Original Message----- > From: Cox, Simon (L&W, Clayton) > Sent: Saturday, 25 February, 2017 15:01 > To: 'Raúl García Castro' <rgarcia@fi.upm.es>; Rob Atkinson < > rob@metalinkage.com.au> > Cc: Maxime Lefrançois <maxime.lefrancois@emse.fr>; SDW WG Public List < > public-sdw-wg@w3.org> > Subject: RE: Link between FeatureOfInterest and xxxProperty > > The relevant standard from the OGC/ISO TC 211 world is ISO 19109 "Rules > for Application Schema" which describes the 'General Feature Model' in > which feature-types are defined in terms of their properties - i.e. > properties are strongly bound with the feature-types that they apply to. > Its really just standard object modelling, but dressed up to use > terminology from the geospatial domain (i.e. "Features" instead of > real-world-objects). > > I was the editor for the most recent edition of ISO 19109:2015, and > managed to get a couple of significant changes relevant to our work here > incorporated > (i) a strong recommendation that properties should be defined and names > carefully to allow them to be re-used on different feature types > (ii) a meta-class for "ValueAssignment" with "Observation" as one of the > concrete instantiations. > > Unfortunately the document is behind ISO's paywall, but I've attached the > three key figures here. > > Also see Figure 2 in the OGC/ISO standard for O&M, available from > http://www.opengeospatial.org/standards/om (get Topic 20, not the XML > implementation). > > Simon > > -----Original Message----- > From: Raúl García Castro [mailto:rgarcia@fi.upm.es] > Sent: Friday, 24 February, 2017 22:43 > To: Rob Atkinson <rob@metalinkage.com.au> > Cc: Maxime Lefrançois <maxime.lefrancois@emse.fr>; SDW WG Public List < > public-sdw-wg@w3.org> > Subject: Re: Link between FeatureOfInterest and xxxProperty > > Dear all, > > I think that being able to represent which properties relate to a certain > feature is a requirement needed both in SOSA and in SSN. > > For example, in the SSN usage analysis > (http://w3c.github.io/sdw/ssn-usage/), even if it is not exhaustive, 3 > ontologies and 2 datasets use the SSN properties to do so. > > So I propose to open an issue to study this in deeper detail. > > Kind regards, > > El 24/2/17 a las 12:18, Rob Atkinson escribió: > > > > the FeatureOfInterest is an abstract class that a domain Class will be > > mapped to in an implementation - so the properties being measured are > > references to the properties defined in that class - i.e. I dont think > > we need to define the link that direction other than somehow stating > > this substitution > > > > i.e. perhaps its defined in the implementation by making a statement > > that domain:Class rdfs:subClassOf sosa:FeatureOfInterest or even that > > there is a restriction on the range on sosa:featureOfInterest to be > > domain:Class > > > > I think its worth an OWL expert to lay out the exact options here in > > examples. > > > > Rob > > > > > > > > > > On Fri, 24 Feb 2017 at 02:24 Maxime Lefrançois > > <maxime.lefrancois@emse.fr <mailto:maxime.lefrancois@emse.fr>> wrote: > > > > Dear all, > > > > Implementing ACTION-268, I stumbled again on the fact that there is > > currently no link between FeatureOfInterest and xxxProperty defined > > in SOSA. > > See also the figure attached > > to > > https://lists.w3.org/Archives/Public/public-sdw-wg/2017Feb/0090.html > > . > > > > I would like us to discuss this shortly during the next call, there > > are two simple options that I listed in the following wiki page: > > > > > > https://www.w3.org/2015/spatial/wiki/Link_between_FeatureOfInterest_an > > d_xxxProperty > > > > For your interest, in one of the core SEAS ontologies we promote the > > definition of "functional sub-properties of ssn:hasProperty". See > > [1]. > > > > For example, some domain ontology would define: > > > > ex:consumption a owl:ObjectProperty , owl:FunctionalProperty ; > > rdfs:subPropertyOf seas:hasProperty ; > > > > Then in static instance data: > > > > <fridge/1> a seas:FeatureOfInterest ; > > ex:consumption <fridge/1/consumption> . > > > > Core ontology seas:EvaluationOntology defines various ways to give > > such Property a value. > > > > [1] - https://w3id.org/seas/FeatureOfInterestOntology > > > > Kind regards, > > Maxime > > > > > > -- > > Dr. Raúl García Castro > http://www.garcia-castro.com/ > > Ontology Engineering Group > Departamento de Inteligencia Artificial > Escuela Técnica Superior de Ingenieros Informáticos Universidad > Politécnica de Madrid Campus de Montegancedo, s/n - Boadilla del Monte - > 28660 Madrid > Phone: +34 91 336 65 96 <+34%20913%2036%2065%2096> - Fax: +34 91 352 48 19 > <+34%20913%2052%2048%2019> > > > > -- > Krzysztof Janowicz > > Geography Department, University of California, Santa Barbara > 4830 Ellison Hall, Santa Barbara, CA 93106-4060 > > Email: jano@geog.ucsb.edu > Webpage: http://geog.ucsb.edu/~jano/ > Semantic Web Journal: http://www.semantic-web-journal.net > >
Received on Tuesday, 28 February 2017 20:00:06 UTC