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Non-dereferencable URIs (was Re: ACTION-255 - o&m alignment)

From: Phil Archer <phila@w3.org>
Date: Wed, 8 Feb 2017 06:48:13 +0000
To: Simon.Cox@csiro.au, public-sdw-wg@w3.org
Message-ID: <e11ade35-adb1-8725-6bac-920d4ce669e2@w3.org>
I'm sorry I wasn't able to speak about this on the call. By the time 
this topic came up I was being driven along the road and had 
insufficient bandwidth to un-mute myself although I could hear the 
conversation.

Of course dereferencable URIs are preferred over non-dereferencable 
ones. However, this should not be seen as an absolute requirement or 
diktat. If there are good reasons to use non-dereferencable URIs - and 
it sounded to me as if Simon was making a very strong case for their use 
- and if the non-dereferencable state causes no harm, then go ahead.

The question is, of course, can TC211 be encouraged to make things like 
http://def.isotc211.org/iso19156/2011/ dereferencable? If it helps, we'd 
happily host the relevant data to which those URIs could redirect (I'm 
sure OGC and others would too of course).

I doubt this would be helpful but we could perhaps mint new ones that 
did dereference and assert equivalence but that's only worth doing if it 
provides some functionality that's actually useful.

Phil



On 07/02/2017 22:26, Simon.Cox@csiro.au wrote:
> I've dropped it into a Wiki page here (formatting not yet complete).
>
> https://www.w3.org/2015/spatial/wiki/Alignment_to_O%26M
>
> This should help with your namespace and prefix questions Laurent.
>
> From: Simon.Cox@csiro.au [mailto:Simon.Cox@csiro.au]
> Sent: Wednesday, 8 February, 2017 08:35
> To: public-sdw-wg@w3.org
> Subject: [ExternalEmail] RE: ACTION-255 - o&m alignment
>
> If you are unable to see the section in the HTML in the branch, here is the proposed text:
>
> -----------------------
>
> 8. Alignment to Observations and Measurements
>
> This section introduces the alignment of SOSA/SSN to OGC Observations and Measurements [OandM] (also known as ISO 19156:2011).
>
> O&M is specified as a UML model, following the patterns specified in ISO 19109 Geographic Information - Rules for Application Schema [ISO-19109]. This means that the classes represent concepts from the application domain, so can be approximately equated with classes in an ontology.
>
> Two OWL implementations of O&M have been described:
>
> an explicit translation of the UML following the rules specified in [ISO-19150-2] - see [OM-Heavy]; and
> a handcrafted version in more idiomatic OWL [OM-Lite].
> The following sections provide two mappings or alignments between SOSA/SSN and O&M: the first with the official ISO/OGC UML conceptual model, and the second with the lightweight OWL implementation.
>
> 8.1 Alignment to Observations and Measurements UML model
>
> This section is non-normative.
>
> The explicit translation generates an RDF entity for every class, class attribute, and association-role from the original O&M UML model. It comes at a cost of a large set of dependencies on similar OWL translations of other UML models from the ISO 19100 series. Nevertheless, the URI for each RDF entity is a convenient identifier to elements of the UML model. These can be used to identify the elements of O&M in a formal RDF/OWL alignment.
>
> Rules for generating the URIs are provided in [ISO-19150-2], and appear in the official OWL implementation of ISO 19156 (O&M) maintained by the ISO/TC 211 Group on Ontology Management.
>
> The following namespace prefixes are used in the alignment to SOSA.
>
> Prefix   Namespace
> sosa:    http://www.w3.org/ns/sosa/
> sosa-om:          http://www.w3.org/ns/sosa-om#
> iso19156-gfi:   http://def.isotc211.org/iso19156/2011/GeneralFeatureInstance#
> iso19156-om:  http://def.isotc211.org/iso19156/2011/Observation#
> iso19156-sf:     http://def.isotc211.org/iso19156/2011/SamplingFeature#
> iso19156-sfs:   http://def.isotc211.org/iso19156/2011/SpatialSamplingFeature#
> iso19156-sp:    http://def.isotc211.org/iso19156/2011/Specimen#
> Utility classes
>
> Five utiity classes are defined locally to support the formalization of the alignment.
>
> 1. Three disjoint subclasses of sosa:Procedure:
>
> sosa-om:ActuationProcedure Actuation procedures or recipes
> sosa-om:ObservationProcedure         Observation procedures or recipes
> sosa-om:SamplingProcedure  Sampling, sample preparation or processing procedures or recipes
> 2. Two classes related to sampling, which complement SOSA classes related to actuation and observation:
>
> sosa-om:SamplingDevice        Sampling, sample preparation or processing devices, comparable to sosa:Actuator and sosa:Sensor
> sosa-om:SamplingEvent          Sampling, sample preparation or processing event or act, comparable to sosa:Actuation and sosa:Observation
> Class alignments
>
> The primary classes from [OandM] have direct equivalents in SOSA classes supplemented by the utility classes described above, as follows:
>
> iso19156-om:OM_Observation          equivalent class          sosa:Observation
> iso19156-om:OM_Process      equivalent class          sosa:Sensor or sosa-om:ObservationProcedure
> iso19156_sf:SF_SamplingFeature       equivalent class          sosa:Sample
> iso19156-sf:SF_Process           equivalent class          sosa-om:SamplingDevice or sosa-om:SamplingProcedure
> Additional alignments from SOSA/SSN classes to O&M classes are as follows.
>
> sosa:FeatureOfInterest           subclass of       iso19156_gfi:GFI_DomainFeature
> where iso19156_gfi:GFI_DomainFeature has the definition:
>
> The class GFI_DomainFeature represents 'real-world' features which are the ultimate subject of an observation campaign, i.e. the features from an application domain that are not artefacts of the observation process (sampling features).
> sosa:Actuator  subclass of       iso19156_gfi:GFI_Feature
> sosa:Platform  subclass of       iso19156_gfi:GFI_Feature
> where iso19156_gfi:GFI_Feature has the definition
>
> The class GFI_Feature represents the set of all classes which are feature types. In an implementation this abstract class shall be substituted by a concrete class representing a feature type from an application schema associated with a domain of discourse (ISO 19109, ISO 19101).
> Property alignments
>
> The following properties from [OandM] have direct equivalents in SOSA properties:
>
> iso19156-om:OM_Observation.featureOfInterest     equivalent property    sosa:hasFeatureOfInterest
> iso19156-om:OM_Observation.observedProperty    equivalent property    sosa:observedProperty
> iso19156-om:OM_Observation.phenomenonTime    equivalent property    sosa:phenomenonTime
> iso19156-sf:SF_SamplingFeature.sampledFeature    equivalent property    sosa:isSampleOf
> Additional alignments from O&M properties to SOSA are as follows.
>
> iso19156-om:OM_Observation.procedure    sub-property of           sosa:usedProcedure
> iso19156-sp:SF_Specimen.samplingMethod  sub-property of           sosa:usedProcedure
> These alignments are modeled as sub-properties because sosa:usedProcedure applies to actuation, observation or sampling activities.
>
> iso19156-om:OM_Observation.result            sub-property of           sosa:hasResult
> iso19156-om:OM_Observation.resultTime    sub-property of           sosa:resultTime
> iso19156-sp:SF_Specimen.samplingTime       sub-property of           sosa:resultTime
> iso19156-sp:PreparationStep.time     sub-property of           sosa:resultTime
> These alignments are modeled as sub-properties because sosa:hasResult and sosa:resultTime applies to actuation, observation or sampling activities.
>
> iso19156-sfs:SF_SpatialSamplingFeature.hostedProcedure   sub-property of           sosa:hosts
> These alignments are modeled as a sub-property because the domain of iso19156-sfs:SF_SpatialSamplingFeature.hostedProcedure is a spatial sampling feature, such as a station, rather than a more general platform.
>
> An RDF file containing a graph corresponding to this alignment is available.
>
> 8.2 Alignment to om-lite implementation of Observations and Measurements
>
> This section is non-normative.
>
> An idiomatic OWL implementation of O&M (including Sampling Features) is described in [OM-Lite].
>
> The following namespace prefixes are used in the alignment to SOSA.
>
> Prefix   Namespace
> sosa:    http://www.w3.org/ns/sosa/
> sosa-oml:         http://www.w3.org/ns/sosa-oml#
> oml:     http://def.seegrid.csiro.au/ontology/om/om-lite#
> samfl:  http://def.seegrid.csiro.au/ontology/om/sam-lite#
> Utility classes
>
> Five utiity classes are defined locally to support the formalization of the alignment.
>
> 1. Three disjoint subclasses of sosa:Procedure:
>
> sosa-oml:ActuationProcedure Actuation procedures or recipes
> sosa-oml:ObservationProcedure        Observation procedures or recipes
> sosa-oml:SamplingProcedure Sampling, sample preparation or processing procedures or recipes
> 2. Two classes related to sampling, which complement SOSA classes related to actuation and observation:
>
> sosa-oml:SamplingDevice       Sampling, sample preparation or processing devices, comparable to sosa:Actuator and sosa:Sensor
> sosa-oml:SamplingEvent         Sampling, sample preparation or processing event or act, comparable to sosa:Actuation and sosa:Observation
> Class alignments
>
> The primary classes from [OM-Lite] have direct equivalents in SOSA classes supplemented by the utility classes described above, as follows:
>
> oml:Observation         equivalent class          sosa:Observation
> oml:Process     equivalent class          sosa:Sensor or sosa-om:ObservationProcedure
> samfl:SamplingFeature           equivalent class          sosa:Sample
> samfl:Process  equivalent class          sosa-om:SamplingDevice or sosa-om:SamplingProcedure
> Property alignments
>
> The following properties from [OM-Lite] have direct equivalents in SOSA properties:
>
> oml:featureOfInterest equivalent property    sosa:hasFeatureOfInterest
> oml:observedProperty            equivalent property    sosa:observedProperty
> oml:phenomenonTime           equivalent property    sosa:phenomenonTime
> samfl:sampledFeature            equivalent property    sosa:isSampleOf
> Additional alignments from [OM-Lite] properties to SOSA are as follows.
>
> oml:procedure            sub-property of           sosa:usedProcedure
> samfl:samplingMethod           sub-property of           sosa:usedProcedure
> These alignments are modeled as sub-properties because sosa:usedProcedure applies to actuation, observation or sampling activities.
>
> oml:result        sub-property of           sosa:hasResult
> oml:resultTime           sub-property of           sosa:resultTime
> samfl:samplingTime   sub-property of           sosa:resultTime
> These alignments are modeled as sub-properties because sosa:hasResult and sosa:resultTime applies to actuation, observation or sampling activities.
>
> samfl:hostedProcedure           sub-property of           sosa:hosts
> These alignments are modeled as a sub-property because the domain of iso19156-sfs:SF_SpatialSamplingFeature.hostedProcedure is a spatial sampling feature, such as a station, rather than a more general platform.
>
> An RDF file containing a graph corresponding to this alignment is available.
>
>
> From: Cox, Simon (L&W, Clayton)
> Sent: Tuesday, 7 February, 2017 15:58
> To: 'Simon.Cox@csiro.au' <Simon.Cox@csiro.au<mailto:Simon.Cox@csiro.au>>; public-sdw-wg@w3.org<mailto:public-sdw-wg@w3.org>
> Subject: RE: ACTION-255 - o&m alignment
>
> Note that this mapping is only from SOSA to O&M (and om-lite).
>
> I also intend to look at the mapping from 'SSN' (i.e. the vertical axiomatization/extension) of SOSA for observations and sensing through to O&M. Much of the intended alignment was captured in annotations in the original ontology, but the discussions in the last week suggest that some local-names might change else SOSA classes and properties used in place of old SSN equivalents. When this has settled down a comprehensive mapping should be formulated.
>
> Probably the key question arising from the work mentioned below is whether the proposal to use the URIs that are specified in the translation of the UML model to OWL, following the ISO 19150-2 rules, is acceptable.
>
> Pro:
>
> -          It allows us to express the alignment formally within the idiom we are working in (OWL)
> Cons:
>
> -          The OWL version of O&M is not in itself published as a 'standard' and the URIs are not directly resolvable (yet, anyway)
>
> o   However, as pointed out in the document, the URIs are persistent identifiers in the view of ISO, and the fact that ISO's process does not require a separate document for the OWL implementation should be OK for us
>
> -          UML and OWL are so different in their assumptions that it is a fallacy to use the OWL implementation as representing the UML model
>
> I'm sure there are other arguments. My feeling is that the proposed approach balances formality and pragmatism OK.
>
> Simon
>
> From: Simon.Cox@csiro.au<mailto:Simon.Cox@csiro.au> [mailto:Simon.Cox@csiro.au]
> Sent: Saturday, 28 January, 2017 21:33
> To: public-sdw-wg@w3.org<mailto:public-sdw-wg@w3.org>
> Subject: [ExternalEmail] ACTION-255 - o&m alignment
>
> In response to my ACTION-255 from last week's meeting, I have generated two RDF files containing formal alignments between SOSA and O&M.
>
> -          sosa-om-mapping.ttl relates to the O&M UML model, and uses the Official ISO URIs from the OWL implementation prepared by the ISO/TC 211 Group on Ontology Management following the rules from ISO 19150-2
>
> -          sosa-oml-mapping.ttl relates to the om-lite and sam-lite OWL implementation recently published in Semantic Web Journal
>
> I have also prepared text for the SSN document describing these mappings - for chapter 8 in the spec.
> So far the mappings only concern SOSA.
>
> I've pushed all this into a branch in GitHub https://github.com/w3c/sdw/tree/simon-ssn-O%26M-alignments/ssn
> and issued a pull-request https://github.com/w3c/sdw/pull/516
>
> Simon
>
> Simon J D Cox
> Research Scientist
> Environmental Informatics
> CSIRO Land and Water<http://www.csiro.au/Research/LWF>
>
> E simon.cox@csiro.au<mailto:simon.cox@csiro.au> T +61 3 9545 2365 M +61 403 302 672
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> researchgate.net/profile/Simon_Cox3<https://www.researchgate.net/profile/Simon_Cox3>
> github.com/dr-shorthair<https://github.com/dr-shorthair>
>
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-- 


Phil Archer
Data Strategist, W3C
http://www.w3.org/

http://philarcher.org
+44 (0)7887 767755
@philarcher1
Received on Wednesday, 8 February 2017 06:48:28 UTC

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