multiple capabilities of the same kind

[Paul Harrison]

On 2008-02 -15, at 14:30, Ray Plante wrote:

> Hi Paul,
>
> Thanks for bringing this up.
>
> On Fri, 15 Feb 2008, Paul Harrison wrote:
>> We have recently come across people wanting to register services  
>> with multiple capabilities of the same kind e.g. a resource with  
>> two capabiities whose standardID="ivo://ivoa.net/std/SIA",
>
> One thing that would be important to know here is what is it that  
> the registrant is trying to accomplish by doing this?  What is it  
> that is distinction between the two SIA capabilities.  By being part  
> of the same resource, it is presumed that both access the same  
> underlying data. Assuming this is true, it could be that the  
> capabiliity metadata is different; if so, why?  If it is simply a  
> matter of providing multiple base URLs for the endpoint of the  
> service, then this can be provided as multiple <accessURL> elements  
> withing the <interface>.

It seems that the motivation behind this is that each capability gives  
access is a different subset of the overall data set, other than that,  
the capability metadata are identical except for the different  
endpoints (and description elements) for each subset. What brought it  
to my attention was precisely that there was no machine readable way  
of telling these endpoints apart - a human can tell them apart by  
reading the description of course.
>
>
>> OR
>>
>> We amend the VOResource schema and add an extra "name" attribute  
>> onto the capability element, which could be used to distinguish  
>> between multiple capabilities with the same standardID by using the  
>> value of the name attribute as the URI "fragment" e.g. ivo:// 
>> org.mytelescope/survey#rband could be used to identify the  
>> individual simple image access capability within the resource.
>
> This is an interesting and appealing idea; however, I note that  
> VOResource has already passed to recommendation.  Thus, this change  
> would have to be handled as a new version of the standard and passed  
> through the process from WD.  Given this, I would recommend that we  
> deal with this cases with the schema we have.


I thought that you might say that ;-)


Dr. Paul Harrison
JBCA, Manchester University
http://www.manchester.ac.uk/jodrellbank