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RE: Alignment of SSN and SOSA (completion of ACTION-246 Prepare a graphical representation of the alignment)

From: Kerry Taylor <kerry.taylor@anu.edu.au>
Date: Wed, 25 Jan 2017 08:04:39 +0000
To: Laurent Lefort <laurent.lefort@abs.gov.au>, "public-sdw-wg@w3.org" <public-sdw-wg@w3.org>
Message-ID: <SYXPR01MB1536C25BA5A990DE1C204C67A4740@SYXPR01MB1536.ausprd01.prod.outlook.com>
Laurent – Thanks for this --- we really need some images.
I’ve had a quick look but can you tell me what the triple equals means? I’m a bit troubled about the appearance that a sosa:Sensor is equivalent to a sosa:Actuator, for example.

-Kerry

From: Laurent Lefort [mailto:laurent.lefort@abs.gov.au]
Sent: Tuesday, 24 January 2017 10:38 PM
To: public-sdw-wg@w3.org
Subject: Re: Alignment of SSN and SOSA (completion of ACTION-246 Prepare a graphical representation of the alignment)


Hi,

I have added graphical representations of the proposed mappings (to serve as basis for discussion for the group on issue-139)
This also corresponds to my ACTION-246: Prepare a graphical representation of the alignment

The diagrams are drawn using a tool created by David Ratcliffe: Owl2Diagram https://github.com/dratc/owl2diagram and are part of the ontology documentation environment we use at ABS.

I have uploaded the images to this wiki page: https://www.w3.org/2015/spatial/wiki/Mapping_Table

(uploading these images here is much faster/convenient for me than through GitHub)
For convenience, I have added here the direct links to the corresponding SVG files.

There are two sets of diagrams:

Simon's alignment (subClassOf) https://github.com/w3c/sdw/blob/simon-ssn/ssn/rdf/ssn-sosa.ttl

... is a bit harder to read because the related stuff is connected by arrows

[1] SOSA: https://www.w3.org/2015/spatial/wiki/images/4/4f/Ontology-complete-sosa.svg

[2] SSN: https://www.w3.org/2015/spatial/wiki/images/3/36/Ontology-complete-ssn.svg



... and Laurent's alignment (also based on the proposed mappings but opting to implement them as owl:equivalentClass/owl:equivalentProperty)
--- is easier to read (and more compact) because the owl2diagram tool creates a single box for equivalence classes.
(the mappings I have used are here: https://www.w3.org/2015/spatial/wiki/images/d/db/Mappings.ttl


[3] SSN: https://www.w3.org/2015/spatial/wiki/images/3/31/Ontology-complete-ssn-equiv.svg

[4] SOSA: https://www.w3.org/2015/spatial/wiki/images/e/ec/Ontology-complete-sosa-equiv.svg

[5]  SSNX: https://www.w3.org/2015/spatial/wiki/images/7/76/Ontology-complete-ssnx-equiv.svg

[6] OM Lite: https://www.w3.org/2015/spatial/wiki/images/d/dc/Ontology-complete-oml-equiv.svg (using the seegrid.csiro .rdf version)
[7] Sampling Features Lite: https://www.w3.org/2015/spatial/wiki/images/6/6c/Ontology-complete-samfl-equiv.svg (using the seegrid.csiro .rdf version)
and
[8] DUL: https://www.w3.org/2015/spatial/wiki/images/9/9f/Ontology-complete-dul.svg


Note that I have done a number of changes (tweaks) to the source ontologies to get images which are representative of the modelling intent.
In particular, I need the input to be OWL2 DL-compliant input because the diagramming tool uses the Hermit reasoner, so I'm using repairing strategies similar to the ones presented in the paper by N. Matentzoglu and B. Parsia OWL Full/DL gap in the field http://ceur-ws.org/Vol-1265/owled2014_submission_9.pdf

Plus there are other changes for prefixes (e.g. ssn moved to ssnx to differentiate the old SSN to the new one).

Also, please note that this is not an endorsement of these alignments. My position is similar to what was explained in the recent emails by Raul and Raphael.
But it is easier to explain now that we have this. We should strive to:
- have a smaller number of boxes in the diagrams and also smaller boxes (maximum two alternatives, not 3 or even 4 (Observation) as is currently the case
- ensure maximum compatibility with the existing SSN
- ensure minimum overlap between the ontologies.
- and finally be capable to explain the added value associated to all the changes we make (and motivate implementers ...).

-Laurent

PS: Phil, the other reason I have not tried via GitHub yet is because I think I'm not yet declared as a contributor there (I was not around when this was set up).

[Inactive hide details for ---24/01/2017 04:30:28 PM---I just created a little file containing an initial proposed mapping from]---24/01/2017 04:30:28 PM---I just created a little file containing an initial proposed mapping from SSN to SOSA and loaded it t

From: <Simon.Cox@csiro.au<mailto:Simon.Cox@csiro.au>>
To: <public-sdw-wg@w3.org<mailto:public-sdw-wg@w3.org>>,
Date: 24/01/2017 04:30 PM
Subject: Alignment of SSN and SOSA

________________________________



I just created a little file containing an initial proposed mapping from SSN to SOSA and loaded it to a branch – see

https://github.com/w3c/sdw/blob/simon-ssn/ssn/rdf/ssn-sosa.ttl


I just followed the alignment shown here: https://www.w3.org/2015/spatial/wiki/Mapping_Table but expressed it more formally so all the alignments are cast as

ssn:XXX rdfs:subClassOf sosa:YYY .
ssn:vvv rdfs:subPropertyOf sosa:uuu .

except for one, which is the other way round because the definition in SOSA seemed to be more restricted than SSN.

sosa:hasValue rdfs:subPropertyOf ssn:hasValue ;
.

I think this matches the discussion today. I issued a pull-request.

In some cases it may be appropriate to replace rdfs:subClassOf with the stronger owl:equivalentClass.

This relates to ISSUE-37, ISSUE-49, ISSUE-88, ISSUE-102, ISSUE-115, ISSUE-139 .

Simon


From: Armin Haller [mailto:armin.haller@anu.edu.au]
Sent: Tuesday, 24 January, 2017 11:46
To: Kerry Taylor <kerry.taylor@anu.edu.au<mailto:kerry.taylor@anu.edu.au>>; janowicz@ucsb.edu<mailto:janowicz@ucsb.edu>; Joshua Lieberman <jlieberman@tumblingwalls.com<mailto:jlieberman@tumblingwalls.com>>
Cc: Rob Atkinson <rob@metalinkage.com.au<mailto:rob@metalinkage.com.au>>; Raúl García Castro <rgarcia@fi.upm.es<mailto:rgarcia@fi.upm.es>>; public-sdw-wg@w3.org<mailto:public-sdw-wg@w3.org>; Cox, Simon (L&W, Clayton) <Simon.Cox@csiro.au<mailto:Simon.Cox@csiro.au>>
Subject: Re: ACTION-251: (ISSUE-88) write up how an ssn:platform and a sosa:platform are essentially the same, with an example (Spatial Data on the Web Working Group)

I can see rapid convergence here in this thread. …


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Received on Wednesday, 25 January 2017 08:05:19 UTC

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