[esip-semantictech] [AGENDA] ESIP SemTech Telecon - 2019-05-28

Tue May 28 19:09:12 EDT 2019

Thanks Blake –
Sorry I missed your presentation. Somehow it had dropped out of my calendar.

I’ve looked through your slides. Your general approach (which I think is to persist geometry representations outside the context of the feature, and link to them through URIs) makes sense, and I think essentially matches practice in GIS systems for decades now (where geometry was in a separate table).

However, I’m not sure that you need a new vocabulary or namespace.   The definition of :hasGeometry in the GeoSPARQL standard[1] (clause 8.3.1.1) is

geo:hasGeometry a rdf:Property,
owl:ObjectProperty;
rdfs:isDefinedBy <http://www.opengis.net/spec/geosparql/1.0>;
rdfs:label "has Geometry"@en;
rdfs:comment "A spatial representation for a given feature."@en;
rdfs:domain geo:Feature;
rdfs:range geo:Geometry .

It is an owl:ObjectProperty, but there is no requirement for the object to be a local blank-node. It can be a URI, as in your slide 18.

You may worry about the rdfs:range, which is given as geo:Geometry, which is defined in clause 8.4. A set of properties are provided, one of which is geo:hasSerialization. WKT is only provided as an example, and is not mandatory - GML is included in GeoSPARQL as another option, but other representations are not prohibited thanks to the RDF open-world-assumption.  There is merely the entailment that the object of a geo:hasGeometry property is a member of the class geo:Geometry.

As you note, content negotiation for representations of a geometry will be helpful.
However, format (serialization) negotiation using HTTP Accept: is only part of the story.
You will likely also need to negotiate over the schematic form of the representation (e.g. neogeo vs geosparql).
This is the topic of an upcoming W3C note from the Data Exchange Working Group ‘Content Negotiation by Profile’[2].

Simon

[1] https://portal.opengeospatial.org/files/?artifact_id=47664
[2] https://w3c.github.io/dxwg/conneg-by-ap/

From: esip-semanticweb [mailto:esip-semanticweb-bounces at lists.esipfed.org] On Behalf Of Blake Regalia via esip-semanticweb
Sent: Wednesday, 29 May, 2019 07:13
To: Mcgibbney, Lewis J (398M) <lewis.j.mcgibbney at jpl.nasa.gov>
Cc: esip-semanticweb at lists.esipfed.org; Mike Daniels <daniels at ucar.edu>
Subject: Re: [esip-semantictech] [AGENDA] ESIP SemTech Telecon - 2019-05-28

Slides from today's presentation:

https://www.slideshare.net/BlakeRegalia/towards-a-more-efficient-paradigm-of-storing-and-querying-spatial-data-on-the-semantic-web

 - Blake Regalia

On Thu, May 23, 2019 at 4:12 PM Mcgibbney, Lewis J (398M) <lewis.j.mcgibbney at jpl.nasa.gov<mailto:lewis.j.mcgibbney at jpl.nasa.gov>> wrote:
Hi esip-semanticweb,
This is a courtesy email regarding preparation for our next telecon.
We will be hosting Blake Regalia, UCSB who will be “…Revisiting the Representation of and Need for Raw Geometries on the Linked Data Web”.

After Blake’s presentation, we will use the remainder of our time to discuss the science-on-shcema.org<http://science-on-shcema.org> proposal which can be found at https://docs.google.com/document/d/1O539ROr9W7FUEDzR2ni2H2Doxx_2zK8AF-sma8pBDe0/edit?usp=sharing
Mike Daniels will be joining us for that.

Our meeting minites can be found at https://docs.google.com/document/d/19agZraGms4vsv7S2SP0SpPWuTtfIQOet4NkyvMUEClQ/edit#heading=h.yn5iw79j9hmd
SemTech Monthly Telecon

  *   4th Tuesday of each month at 4pm Eastern
  *   GoToMeeting: https://www.gotomeeting.com/join/976796333
  *   Phone Access: United States: +1 (872) 240-3212
  *   Access Code: 976-796-333

Lewis

Dr. Lewis John McGibbney Ph.D., B.Sc.(Hons)
Data Scientist III
Computer Science for Data Intensive Applications Group (398M)
Instrument Software and Science Data Systems Section (398)
Jet Propulsion Laboratory
California Institute of Technology
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Tel:  (+1) (818)-393-7402
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Email: lewis.j.mcgibbney at jpl.nasa.gov<mailto:lewis.j.mcgibbney at jpl.nasa.gov>
ORCID: orcid.org/0000-0003-2185-928X<http://orcid.org/0000-0003-2185-928X>

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