RE: Spatial context

Ø  The definition of 'feature'  in paragraph 4.6 caught my eye. A feature is an 'abstraction of real world phenomena'. Could we say that the OGC feature equals the W3C information resource? Is a collection of data about Greater London a feature and Greater London itself not?

Good question. It depends on how seriously you want to take the distinction between the real-world-object, and a document or record providing some information about it – the so-call HTTP Range 14 question. There have been many discussions on this over many years. Kent’s excellent 1978 book “Data and Reality” is still a good read on the topic. It has just reared its head again on the RDF Shapes list – see ‘shape as a relationship not a class’ in https://lists.w3.org/Archives/Public/public-data-shapes-wg/2015Feb/thread.html . The purists (which usually includes myself) sees some significant benefit in making the distinction. But the rest of the web world largely ignores it. See this smack down from Richard Cyganiak for example - https://lists.w3.org/Archives/Public/public-lod/2011Jun/0186.html


In the O&M Model GFI_Feature was introduced to provide a target for the relationship ‘feature of interest’.
O&M provides a model which conceives an Observation as an event whose intention is to obtain an estimate of the value of some property of a feature. When the model was devised the intention was for it to model things in the world, but in practice, in a data system, the records act as proxies for those. Make of that what you will.


Ø  To me it is just strange to publish a standard that should help the world in getting things done and restrict access to it at the same time.

I’m inclined to agree. Level of usage is the key measure of a standard. ISO is stuck with a real challenge here: it is actually a private company; it does not have membership fees; and historically it has charged for documents to cover its business costs. But these geographic information standards are run through ISO because some governments require standards to be issued by a recognised standards authority before they will officially adopt them. At the time that ISO/TC 211 started its work (in the mid 1990s) it was a reasonable choice. Arguably internet standards have no business hidden behind fees. Perhaps those governments should provide funding so that ISO can run its business and not charge fees for the results. Perhaps it should be supported by UNESCO.

Your example of the Bangladeshi developer is apt. What I find less comprehensible is academics who won’t consult ISO standards because of the paywall, yet rely on articles from journals whose subscription fees can be orders of magnitude larger.

Simon


From: Frans (Geodan) [mailto:frans.knibbe@geodan.nl]
Sent: Monday, 23 February 2015 1:39 AM
To: Cox, Simon (L&W, Highett); public-sdw-wg@w3.org
Subject: Re: Spatial context


On 2015-02-19 21:47, Simon.Cox@csiro.au<mailto:Simon.Cox@csiro.au> wrote:

Ø  … 'Feature': “..equivalent to GFI_Feature defined in ISO 19156:2011”. Unfortunately GFI_Feature as defined in ISO 19156:2011 is not a web resource and ISO 19156:2011 is not an open standard (because you have to pay for it). But it's a start...

ISO 19156:2011 is jointly published by OGC as Topic 20 of their Abstract Spec, and available freely here: http://www.opengeospatial.org/standards/om or directly from www.opengis.net/doc/om<http://www.opengis.net/doc/om>

Thank you Simon, this document can be valuable input if we want to work on clarifying our basic concepts.

The definition of 'feature'  in paragraph 4.6 caught my eye. A feature is an 'abstraction of real world phenomena'. Could we say that the OGC feature equals the W3C information resource? Is a collection of data about Greater London a feature and Greater London itself not?

Paragraph D.1 seems very useful in shedding light on the basic concepts that we will work with (features, coverages, observations).



(Side question: does payment=”not open”? On that basis almost the entire academic literature is “closed”, since you can only read it if you have a subscription! Ditto most books. I agree that the ISO business model is tedious, and does not meet modern expectations for web standards, but an argument can easily be made that ISO standards are indeed “open” as there is no limitation on access to the document other than buying it, and then there is no limitation on use. )
Well, in my book payment for a standard means it is not open. But of course opinions can differ. This wikipedia article<http://en.wikipedia.org/wiki/Open_standard> has an overview of some definitions of what constitutes an open standard.  In Spanish and Danish law for example, an Open Standard really should be free of charge, so the article says.

To me it is just strange to publish a standard that should help the world in getting things done and restrict access to it at the same time. Payment is a barrier that blocks access. For some it is tedious (I think I could get the money but it would take me some bureaucratic effort) but I imagine the payment makes the standard unreachable for others (thinking of a lone web developer in Bangladesh). Besides that, when you do have access to a single standard document in most cases reading it will show that you need some other standards as well (ISO 19156:2011 has twelve references to other ISO standards documents, for example).

But I think it is modern OGC policy to publish OGC versions of the ISO 191** standards for free? That is a good thing. Is it easy to translate references to ISO 191** documents to equivalent OGC documents?

Greetings,
Frans





From: Frans (Geodan) [mailto:frans.knibbe@geodan.nl]
Sent: Friday, 20 February 2015 12:14 AM
To: public-sdw-wg@w3.org<mailto:public-sdw-wg@w3.org>
Subject: Re: Spatial context


I think that the question whether data are spatial data largely depends on the data publisher. The designation “Greater London” could be published as a text label, in which case it is not spatial data. It could also be published as a toponym, in which it is spatial data.

This discussion seems to point at an important requirement for our work, which may or may not be derived from use cases, but still is important: We need clear and universal semantics.

What makes a thing spatial? Does it have to have geometry? Does it have to have three dimensions? Does it need to be a terrestial object? Does it need to be non-fictional? All these things are debatable, but rather than debate them it would be good to have agreed upon semantics.

At the moment, there are some definitions out there on the semantic web. For example, the Location Core Vocabulary<http://www.w3.org/ns/locn> defines the concept 'location'. Unfortunately the definition is self-referencing: “any location, irrespective of size or other restriction”. In other words, it is very open to interpretation. Is “Paris” a location (knowing that there are multiple locations with that name)? Is Atlantis (fictional) a location? Is Olympus Mons (on Mars) a location?

GeoSPARQL<%28http:/www.opengis.net/ont/geosparql> has definitions for the concept 'SpatialObject': “..everything that can have a spatial representation” (unfortunately the 'spatial representation' part is undefined) and 'Feature': “..equivalent to GFI_Feature defined in ISO 19156:2011”. Unfortunately GFI_Feature as defined in ISO 19156:2011 is not a web resource and ISO 19156:2011 is not an open standard (because you have to pay for it). But it's a start...

Greetings,
Frans


On 2015-02-19 11:50, Ed Parsons wrote:
This is a great discussion and I think it is central to the potentially difficult overlap between the two community perspectives.

I'm sure Josh will chip in but I do think we need to recognise that we need to include spatial information for which it is not possible to define a geometry or have linked to as an attribute - This I think is what Josh means by context, I am writing this email from a location within "Central London" although there is not a canonical geometry that represents the shape of central London.

This is an example of what Mike Goodchild calls a Platial Problem !

This must be in scope, does the current wording around spatial information accommodate it ?

Ed


On Thu Feb 19 2015 at 10:26:55 Andrea Perego <andrea.perego@jrc.ec.europa.eu<mailto:andrea.perego@jrc.ec.europa.eu>> wrote:
Andreas's mail gives me the opportunity to explain the objection I
raised during the call [1] about the proposal of adding "spatial
context" into scope question #1 [2].

My main concern is that the use of "spatial context" in the scoping
question may be confusing, and probably unnecessary.

In my understanding, spatial context is specified through spatial data
- i.e., it denotes one of their possible uses. So, "spatial data"
should be inclusive enough - it would cover spatial data as a whole,
irrespective of their use.

Thanks!

Andrea

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[1]http://www.w3.org/2015/02/18-sdw-minutes.html

[2]http://www.w3.org/2015/spatial/wiki/Scope_questions_and_Requirements


On Wed, Feb 18, 2015 at 10:10 PM, Andreas Harth <harth@kit.edu<mailto:harth@kit.edu>> wrote:
> Hi,
>
> the issue I had with the term "spatial context" is that I did not know
> what the "context" part was supposed to mean.
>
> If I understood Josh correctly, he mentioned that a geometry,
> a place description or a spatial feature should be referenceable
> in data.
>
> If "spatial context" does mean that, I'm fine with the phrasing of
> the scoping question.
>
> Cheers,
> Andreas.
>



--
Andrea Perego, Ph.D.
Scientific / Technical Project Officer
European Commission DG JRC
Institute for Environment & Sustainability
Unit H06 - Digital Earth & Reference Data
Via E. Fermi, 2749 - TP 262
21027 Ispra VA, Italy

https://ec.europa.eu/jrc/


----
The views expressed are purely those of the writer and may
not in any circumstances be regarded as stating an official
position of the European Commission.



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