Re: The SSN requirement 'Reference external vocabularies'

josh,
Your  concept of stubs or placeholders was always intended in the design of ssn. Units of measurement, and location, and even sensor measurements, for example, are not explicitly covered in ssn but you can see examples of external vocabs used for this in the final report on the wiki. the idea was very much to avoid mandating aspects not specifically about sensing. 

The DUL alignment came late in the development, and was meant to be optional, but somehow became much too closely integrated ( through an import). However, this was rectified some time after the xg closed, and our own charter refers to a modularised ssn  wrt  which dul is altogether optional , but can be brought in via some alignment axioms in another little ontology fragment.

Frans, I  interpreted the externally managed controlled vocabs use case as something entirely different to this. I thought it meant using something like skos -defined terms( ie individuals) in some places. That may be my error, but if it is meant to refer to the idea of being used together linking to another ontology( which is surely just totally normal practice) then  I think it would need some rewording. 

Kerry

> On 7 Oct 2015, at 9:52 pm, Jon Blower <j.d.blower@reading.ac.uk> wrote:
> 
> +1. Sorting out how to encode units of measure would be very useful. There are a few relevant things out there, but I haven’t seen anything that looks to me like the “last word” on the subject.
> 
> Jon
> 
>> On 6 Oct 2015, at 12:59, Joshua Lieberman <jlieberman@tumblingwalls.com> wrote:
>> 
>> Frans,
>> 
>> Yes, I the that would be a good reminder of our goal. A vocabulary for units might not be all explicitly "spatial" but at least the length, area, volume, etc. units are needed for expressing spatiality of data.
>> 
>> Josh
>> 
>> On Oct 6, 2015, at 05:40, Frans Knibbe <frans.knibbe@geodan.nl> wrote:
>> 
>>> 
>>> 
>>> 2015-06-05 19:07 GMT+02:00 Joshua Lieberman <jlieberman@tumblingwalls.com>:
>>>> We have had some discussion of linking and referencing vocabularies at this week’s OGC TC meeting. My sense is that the requirement is both important and spatial. First of all, we are talking about requirements for construction of a spatial vocabulary (SSN) so how we go about it is a a reasonable concern. Beyond this, however, there is need for specific types of references to external vocabularies in order to present a complete spatiotemporal sensing theory without doing too much re-invention. There are conflicting theories in involved in many upper ontologies from which SSN and other spatial ontologies might derive, so choice of inheritance is a concern. Definition of mapping relationships rather than inheritance might be more appropriate.
>>>> 
>>>> Then are there many choices of external vocabularies for other aspects of sensing, such as units, CRS’s, phenomena, etc. There is danger of brittleness in making hard references to specific vocabularies that play these roles, but they are needed for a complete theory. What seems as if it might be more resilient is to be able to create logically consistent stubs or placeholders that define the role an external vocabulary will play in a specification such as SSN without making the vocabulary dependent on a specific vocabulary. To the extent that such vocabularies need to be consistent with SSN theory, the construction of such reference objects is explicitly spatial.
>>> 
>>> Josh,
>>> 
>>> Thank you for your thoughts. Am I right in understanding that you are saying that SSN should not be a closed model with regard to spatial information? Is this a known weakness in the current SSN?
>>> 
>>> Perhaps it would help if we make the spatial angle more clear in the requirment, for example change
>>>  "It should be possible to refer to externally-managed controlled vocabularies."
>>> to
>>>  "It should be possible to refer to externally-managed controlled vocabularies for expressing spatial data."
>>> 
>>> Regards,
>>> Frans
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>>  
>>>> 
>>>> -Josh
>>>> 
>>>> Joshua Lieberman, Ph.D.
>>>> Principal
>>>> Tumbling Walls
>>>> jlieberman*tumblingwalls.com
>>>> +1 617 431 6431
>>>> 
>>>>> On Jun 5, 2015, at 9:48 AM, Frans Knibbe <frans.knibbe@geodan.nl> wrote:
>>>>> 
>>>>> Hello all,
>>>>> 
>>>>> The tracker does not yet send notifications of new issues to this list, so this is a manual notification that I have created ISSUE-20.
>>>>> 
>>>>> This thread can be used to discuss the issue.
>>>>> 
>>>>> 
>>>>> Greetings,
>>>>> Frans
>>>>> 
>>>>> -- 
>>>>> Frans Knibbe
>>>>> Geodan
>>>>> President Kennedylaan 1
>>>>> 1079 MB Amsterdam (NL)
>>>>> 
>>>>> T +31 (0)20 - 5711 347
>>>>> E frans.knibbe@geodan.nl
>>>>> www.geodan.nl
>>>>> disclaimer
>