Re: Best Practice sub-team call: 14:00 UTC, 20-April-2016

Regrets over having a conflict for today’s call. It will be useful to define what is meant or covered by “spatial ontology”. A notion of things that might mean is covered here: http://www.w3.org/2005/Incubator/geo/XGR-geo-ont-20071023/ <http://www.w3.org/2005/Incubator/geo/XGR-geo-ont-20071023/>

ISO 19107 covers geometries and operators, but the feature model as presented in 19109 is perhaps more relevant to the semantic question whether features are relevant on the Web. My sense is that feature discernment is relevant everywhere but there is resistance to the “complexity” of being explicit about it in Web content.

The biggest hurdle may still be the divide between coordinate sequences as literals and coordinates as individual objects. Amazingly, that colors almost every aspect of debates over spatial ontologies, such as whether single latitude and longitude properties are enough  for anything worthwhile on the web.

Lastly, “webbiness” is good, but so is geometric and geodetic validity and consistency. The BP group should consider adopting the GeoSPARQL ontology as a best first start and charging OGC with developing a normative update to that. Everyone likes to make their own ontology, but the compatibility and computability issues then make for problems in large-scale spatial data representations.

—Josh


Joshua Lieberman, Ph.D.
Principal
Tumbling Walls
jlieberman*tumblingwalls.com
+1 617 431 6431

> On Apr 20, 2016, at 5:53 AM, Frans Knibbe <frans.knibbe@geodan.nl> wrote:
> 
> Hello Jeremy,
> 
> Thank you for acknowledging the issue. Yes, I can try to introduce the problem in the meeting. If we decide we could try working towards the spatial ontology there are still a lot of ways in which we could do that. To start with
> the mathematical foundations was just a suggestion. Another step could be to take a good look at ISO 19107 abstract model and see how that fits web requirements and see if it is possible to make that model available as web semantics, to be used as a foundation for other web models involving spatial data. 
> 
> Regards,
> Frans
> 
> 
> 
> 2016-04-19 23:28 GMT+02:00 Jeremy Tandy <jeremy.tandy@gmail.com <mailto:jeremy.tandy@gmail.com>>:
> Frans - thanks for the suggestion. Simon, Andrea - thanks for discussion. Certainly a thorny issue to resolve, but one that we need to address openly and transparently. Even if a single solution cannot be found, we _will_ need to document the reasons why a single solution is not possible - which will help us establish [best] practices for when and where each of the multiple solutions should be used. Of course, life would be easier with one solution; so we should begin by striving for that.
> 
> If we're going to start from mathematical foundations, this sounds like a rigorous piece of work. Would it be best published as an independent Note? (the WG has the remit to do so if we see fit).
> 
> I've updated the agenda [1] to include the proposed topic (see below). Frans - can you take the lead on this subject please? Given that this is a massive topic, we won't finish the discussion in one meeting! So I will time-box the discussion to 30-mins to allow for time to discuss other items.
> 
> Part 1 (30-mins): establishing an "agreed spatial ontology"
> [Frans] problem statement
> solution criteria - what do we need the "agreed spatial ontology" to do?
> prior art - what can we learn from (and where are the overlaps and gaps in existing work)
> define plan of work - how do we move forward; who will lead?
> 
> [1]: https://www.w3.org/2015/spatial/wiki/Meetings:BP-Telecon20160420#Main_agenda <https://www.w3.org/2015/spatial/wiki/Meetings:BP-Telecon20160420#Main_agenda>
> 
> On Tue, 19 Apr 2016 at 11:57 Frans Knibbe <frans.knibbe@geodan.nl <mailto:frans.knibbe@geodan.nl>> wrote:
> Yes, it would be tough issue. But I am afraid that not addressing the issue properly will incur much greater costs. Perhaps not on our group, but certainly on society and the web as a whole. But also within our group there can be immediate benefits of having a basic spatial ontology. I have the feeling that many of the problems we are trying to solve are are a result of the absence of a solid theoretical foundation of the things we try to work with. We are mostly scratching the surface instead of attacking the core issues. I think it is likely that if the few core issues are resolved satisfactorily, many other problems will cease to be problems. 
> 
> I also think that the undertaking of defining a spatial ontology can be broken up in consecutive steps. We do not need to finish all those steps in order to be successful. But we can leave a solid foundation for others to continue with.
> 
> To keep things simple, a first goal could be just to define vector geometry as a data type. Having just that would solve a lot of interoperability problems and would clear the way for universal ways of storing and exchanging spatial data. Humanity has been able to do the same for numbers and text, and having agreed upon models for those data types makes IT a lot simpler than it would have been if there was no such agreement. 
> 
> So a first step could be defining vector geometry as a mathematical construct, an ordered set of coordinates in some reference system. Much could be built on top of such a foundation, and even if in the end there would still be need for different serializations of geometry, it would help if those serializations share a common base model - going to a more basic level would achieve interoperability. And if the mathematical foundations are solid, a lot of derived ways of working with spatial data (transformations, spatial relationships, topology,...) will be much easier to set up. And as said before, we would also have a common ground for geographic geometry and non-geographic geometry, so that we can use methods from both worlds interchangeably. 
> 
> Perhaps what has been going on in the area of improving temporal data on the web can be an example for spatial data. I noticed that when a mathematical approach to time is adopted, the difference between time instants and time intervals disappears. On the surface there still is a difference, but at the core the situation is simpler. At the core, the concept of time is more unified than all the different expressions that can be encountered in the wild. I think that the same principle - going to the core of the matter to make things simpler and more universal - can also be applied to spatial data.
> 
> Regards,
> Frans
> 
> 
> 
> 2016-04-19 1:36 GMT+02:00 <Simon.Cox@csiro.au <mailto:Simon.Cox@csiro.au>>:
> +1 for considering this openly.
> 
> It is probably the issue that the wider community would most expect to see dealt with in the WG. However, it is definitely a tough issue, and I’m sceptical that it is possible or even desirable to imagine that a single solution is necessary.
> 
>  
> 
> From: Frans Knibbe [mailto:frans.knibbe@geodan.nl <mailto:frans.knibbe@geodan.nl>] 
> Sent: Monday, 18 April 2016 11:42 PM
> To: Jeremy Tandy <jeremy.tandy@gmail.com <mailto:jeremy.tandy@gmail.com>>
> Cc: SDW WG Public List <public-sdw-wg@w3.org <mailto:public-sdw-wg@w3.org>>
> Subject: Re: Best Practice sub-team call: 14:00 UTC, 20-April-2016
> 
>  
> 
> Hello Jeremy,
> 
>  
> 
> Could this meeting be an opportunity to discuss the 'agreed spatial ontology' mentioned in the charter (also see this e-mail thread <https://lists.w3.org/Archives/Public/public-sdw-wg/2016Mar/0057.html>)? I feel it could be the most crucial contribution to the data web our group could make, so it would be good to have more clarity on whether and how we wish to pursue this.
> 
>  
> 
> Regards,
> 
> Frans
> 
>  
> 
> 2016-04-18 12:09 GMT+02:00 Jeremy Tandy <jeremy.tandy@gmail.com <mailto:jeremy.tandy@gmail.com>>:
> 
> All. For those participating in the Best Practices sub-team, the next meeting is scheduled for 14:00 UTC this Wednesday (20-April).
> 
>  
> 
> Preliminary agenda is here: https://www.w3.org/2015/spatial/wiki/Meetings:BP-Telecon20160420 <https://www.w3.org/2015/spatial/wiki/Meetings:BP-Telecon20160420>
>  
> 
> Please advise if you want to add anything. If you can't make the meeting, please record your 'regrets', else we'll see you there.
> 
>  
> 
> Regards - Jeremy, Linda and Payam.
> 
>  
> 
>  
> 
>  
> 
>  
> 
> 
>