Re: Does 'Feature' = 'Real World Thing'?

Thanks Linda. This seems to be a topic that we need to include in the BP
doc. It's an identification problem that's specific to our geospatial
community.
On Mon, 19 Oct 2015 at 08:25, Linda van den Brink <l.vandenbrink@geonovum.nl>
wrote:

> Hi all,
>
>
>
> IMO what we call features in the geospatial domain are usually
> abstractions of representations on maps of real world things; not
> abstractions of real world things themselves. I see this a lot in
> information models in the Netherlands. For example, we have two information
> models that have features of class Building. They both model exactly the
> same set of objects, but one model captures the building geometry as seen
> from above, the other from ground level. Different features, same real
> world thing...
>
>
>
> Linda
>
>
>
> *Van:* Jeremy Tandy [mailto:jeremy.tandy@gmail.com]
> *Verzonden:* maandag 19 oktober 2015 8:43
> *Aan:* SDW WG Public List
> *Onderwerp:* Does 'Feature' = 'Real World Thing'?
>
>
>
> Hi-
>
>
>
> I've been working through the discussion on Linking-Data and this
> uncovered (or, really, re-found) this issue.
>
>
>
> By OGC terminology, Feature is "an abstraction of a real world
> phenomenon". Linked Data folks like to talk about Real World Things (both
> physical and abstract).
>
>
>
> There's a disjoint here that we need to resolve.
>
>
>
> I've captured the question on the wiki [1] and included the content below.
>
>
>
> Jeremy
>
>
>
> [1]:
> https://www.w3.org/2015/spatial/wiki/Linking_Data#Question:_is_a_Feature_the_Real_World_Thing.3F
>
>
>
> Question: is a Feature the Real World Thing? ISO 19101 -- *Geographic
> information - Reference model* states:
>
> ·         [4.11] *feature*: abstraction of real world phenomena
>
> ·         [4.12] *feature attribute*: characteristic of a feature ...
>
> ·         EXAMPLE 2 A feature attribute named ‘length’ may have an
> attribute value ’82.4’ which belongs to the data type ‘real’.
>
> The definition of *feature attribute* is clear- it's a piece of
> information about the *feature*.
>
> *feature* is not quite so clear. In this context, what does *abstraction*
>  mean?
>
> Typically, the Linked Data community refer to *Real-world ‘Things’* (see Designing
> URI sets for the UK public sector
> <https://www.gov.uk/government/publications/designing-uri-sets-for-the-uk-public-sector>
> ); *real-world Things* (or just *Things*) are "are the physical and
> abstract ‘Things’ that may be referred to in statements". Examples include
> a school, a road, a person (physical); a government sector, an ethnic
> group, an event (abstract).
>
> A commonly used example is Manchester Piccadilly Railway Station. A URI
> for Manchester Piccadilly Railway Station would refer to the *real* station,
> constructed from steel and concrete with thousands of people passing
> through it each day. Clearly one cannot expect an HTTP request to return
> the real railway station (!); it returns an information object *about* the
> railway station.
>
> W3C URLS in Data (FPWD) <http://www.w3.org/TR/urls-in-data/> discusses
> the need to differentiate between the real Thing and the information
> resource that describes it. The Publishing Data
> <http://www.w3.org/TR/urls-in-data/#publishing-data> section provides
> three strategies for doing so.
>
> In the Geographic Community, the *Feature* is seen as an information
> resource - which is, in some way, related to the real-world Thing. INSPIRE (Generic
> Conceptual Model
> <http://inspire.ec.europa.eu/documents/Data_Specifications/D2.5_v3.4.pdf>)
> refers to these resources as *Spatial Objects*: "abstract representation
> of a real-world phenomenon related to a specific location or geographical
> area". It notes that the term is "synonymous with "(geographic) feature" as
> used in the ISO 19100 series" and, later, talks about versioning the
> Spatial Objects. Clearly, you can only version the record of information
> held *about* a real world Thing, not the Thing itself?
>
> So the question remains: are we identifying real-world Things (both
> physical and abstract) or information objects that describe them? Once
> that's decided, we need to get our terminology clear and stick to it!
>
>
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>