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Re: Do we need to reference all three sets of spatial relations from GeoSPARQL in BP14?

From: Matthew Perry <matthew.perry@oracle.com>
Date: Tue, 14 Mar 2017 10:46:27 -0400
To: public-sdw-wg@w3.org
Message-ID: <3431f14c-5286-5976-54a2-9c9169f90cf9@oracle.com>
I agree with Ed. Give strong guidance to use simple features and do not 
mention the others to reduce confusion.

Cheers,
Matt


On 3/14/2017 10:03 AM, Ed Parsons wrote:
> I tend to agree with 1) stronger guidance on the commonly used 
> "simple" relationships and given this 2) not mentioning the others...
>
> Ed
>
>
> On Tue, 14 Mar 2017 at 09:45 Jeremy Tandy <jeremy.tandy@gmail.com 
> <mailto:jeremy.tandy@gmail.com>> wrote:
>
>     Hi-
>
>     BP14 [1] is now updated (and probably too large and unwieldy in
>     its current form - we plan to discuss refactoring in Delft during
>     the general BP doc restructuring discussion).
>
>     However, one quick question might be resolvable before Delft.
>
>     In "Possible Approach to Implementation" BP14 talks about the
>     types of links that might be used. Section "2. Spatial
>     relationships" discusses topological relationships. It states:
>
>     > [GeoSPARQL] defines three families of topological relationships
>     (simple features, Egenhofer and RCC8) all of which are based on
>     the DE-9IM <https://en.wikipedia.org/wiki/DE-9IM> pattern, which
>     specifies the spatial dimension of the intersections of the
>     interiors, boundaries and exteriors of two geometric objects that
>     may be 2-dimensional (e.g. area), 1-dimensional (e.g. linear) or
>     0-dimensional (e.g. point).
>
>     ... and ...
>
>     >Details of the Simple Features, Egenhofer and RCC8 (Region
>     Connection Calculus
>     <https://en.wikipedia.org/wiki/Region_connection_calculus>)
>     topological relations families are provided in [GeoSPARQL] section
>     7 Topology Vocabulary Extension.
>
>     BP14 identifies that the simple features relationship family is
>     the most commonly used. The [exam] questions for you are:
>     1/ should we be stronger with the guidance on using simple
>     features relationships over those from the other families?
>     2/ do we even need to mention the other two families? (to my
>     untrained brain, they're just confusing!)
>
>     Thanks in advance.
>
>     Jeremy
>
>     [1]: http://w3c.github.io/sdw/bp/#entity-level-links
>
> -- 
>
>
> *Ed Parsons *FRGS
> Geospatial Technologist, Google
>
> +44 7825 382263 @edparsons
> www.edparsons.com <http://www.edparsons.com/>
>
Received on Tuesday, 14 March 2017 14:47:13 UTC

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