Re: UCR ISSUE-23: phrasing of the spatial operators requirement

2015-10-08 9:11 GMT+02:00 Linda van den Brink <l.vandenbrink@geonovum.nl>:

> Hi all,
>
>
>
> First of all, is it very important that the requirements can be understood
> by everybody? This is very important for the Best Practice, but for the UCR
> document it’s most important that we ourselves can understand it.
>

I can think of several reasons to have very clear requirements:

   1. We want people from outside out workgroup to review what we are
   doing. So a broad audience needs to be able to understand our work;
   2. Within the working group there are people with different backgrounds
   (semantic web, geoinformatics, ..). We have noticed that this is an extra
   reason to make sure everyone understands things the same way;
   3. It would be a good thing if we can present a complete and
   understandable 'chain of evidence' for our next deliverables. For instance,
   Best Practices will be linked to requirements, which are linked to use
   cases. In that sense, the UCR document will be part of the other
   deliverables;
   4. For some deliverables (time, SSN and coverages) it is expected that
   outside parties will be actively involved. So they need to understand the
   requirements too.



>
> But adding something about the purpose of spatial operators, as you
> suggest, does make the text clearer. So no harm in adding it and we can
> reuse this in the BP.
>
>
>
> Linda
>
>
>
> *Van:* Frans Knibbe [mailto:frans.knibbe@geodan.nl]
> *Verzonden:* woensdag 7 oktober 2015 19:14
> *Aan:* SDW WG Public List
> *Onderwerp:* UCR ISSUE-23: phrasing of the spatial operators requirement
>
>
>
> Hello,
>
>
>
> This thread can be used for discussion of UCR issue 23
> <https://www.w3.org/2015/spatial/track/issues/23>: phrasing of the spatial
> operators requirement
> <http://w3c.github.io/sdw/UseCases/SDWUseCasesAndRequirements.html#SpatialOperators>.
> Currently the requirment reads: "There should be a recommended way for the
> definition and use of spatial operators. Spatial things can have spatial
> relations: topological relations, directional or distance relations.
> Operators based on these relations (e.g. 'Contains'. 'Intersects',
> 'Nearest') should be well defined and easy to use.". This issue is about
> clarity of the requirement, keeping in mind that people with different
> backgrounds should understand the requirement.
>
>
>
> Questions that can be asked are:
>
>
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> 1) Is it clear what is meant by 'operators'?  Is the difference between
> operators and relationships clear (compare GeoSPARQL fucntions and
> relationships)? For spatial relationships there is a separate requirement
> <http://w3c.github.io/sdw/UseCases/SDWUseCasesAndRequirements.html#SpatialRelationships>.
> Perhaps we should add something about the purpose of spatial operators (to
> filter, select or derive data)?
>
>
>
> 2) Should we specify that we understand operators to work on numerical
> (coordinate) data only? Could there be a need to support a query like 'give
> me all oases in the Sahara desert' when there is no way to compute the
> answer based on geometry (because the Sahara desert has no clear boundary)?
> Or put in another way: Would it be a problem if we leave the way operators
> should be implemented open, for phrasing the requirement?
>
>
>
> Next to these questions, if you think there are other ways in which the
> requirement is unclear or could be improved, please share your thoughts!
>
>
>
> Regards,
>
> Frans
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