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

From: Jeremy Tandy <jeremy.tandy@gmail.com>
Date: Tue, 14 Mar 2017 13:44:08 +0000
Message-ID: <CADtUq_2aB_vDF2bFatsGQPN18CqCiYL1-U43OfXH5kh0a-KrSQ@mail.gmail.com>
To: SDW WG Public List <public-sdw-wg@w3.org>
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
Received on Tuesday, 14 March 2017 13:44:51 UTC

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