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RE: Spatial relations - was RE: Request for help: BP 9 "How to describe relative positions"

From: <Simon.Cox@csiro.au>
Date: Fri, 2 Sep 2016 01:27:55 +0000
To: <jeremy.tandy@gmail.com>, <jlieberman@tumblingwalls.com>
CC: <eparsons@google.com>, <public-sdw-wg@w3.org>
Message-ID: <0660e7737a224ff4982758c943507339@exch4-mel.nexus.csiro.au>
Yes – that would be very helpful.

From: Jeremy Tandy [mailto:jeremy.tandy@gmail.com]
Sent: Friday, 2 September 2016 2:28 AM
To: Cox, Simon (L&W, Clayton) <Simon.Cox@csiro.au>; jlieberman@tumblingwalls.com
Cc: eparsons@google.com; public-sdw-wg@w3.org
Subject: Re: Spatial relations - was RE: Request for help: BP 9 "How to describe relative positions"

@simon - that's perfect. Do you agree that it would be a good idea to get these registered as Link Relation types on the IANA registry?

I think the definitions are also in your document [1] for input into the registry ...


[1]: https://www.w3.org/TR/owl-time/#vocabulary

On Thu, 1 Sep 2016 at 08:56 <Simon.Cox@csiro.au<mailto:Simon.Cox@csiro.au>> wrote:
For temporal relations, I re-drafted a diagram from one of Allen’s papers:

From: Jeremy Tandy [mailto:jeremy.tandy@gmail.com<mailto:jeremy.tandy@gmail.com>]
Sent: Wednesday, 31 August 2016 9:43 PM
To: Joshua Lieberman <jlieberman@tumblingwalls.com<mailto:jlieberman@tumblingwalls.com>>; Cox, Simon (L&W, Clayton) <Simon.Cox@csiro.au<mailto:Simon.Cox@csiro.au>>
Cc: eparsons@google.com<mailto:eparsons@google.com>; public-sdw-wg@w3.org<mailto:public-sdw-wg@w3.org>
Subject: Re: Request for help: BP 9 "How to describe relative positions"

Finally, I also note that I still need help on the "spatial relations" topic that was second in my original email. More help required please.


On Wed, 31 Aug 2016 at 10:26 Jeremy Tandy <jeremy.tandy@gmail.com<mailto:jeremy.tandy@gmail.com>> wrote:

BP doc section § 10.5.1 "Describing location" [1] is where we intend to provide all the guidance that explains how you should encode location information in a web-friendly way.

This includes BP 8 "Provide geometries on the Web in a usable way" [2] and BP 9 "How to describe relative positions" [3].

(I think it's likely that we will also need a BP to help people choose the right CRS too ...)

We editors envisage BP 9 covering:

(1) Linear referencing
(2) Use of spatial relations [4]



We also want to demonstrate how spatial relations are used. There are obvious examples of topological relationships such as "this administrative unit _touches_ that administrative unit" (or contains etc.).

I recall that we were going to get the set of topological relationships added to the IANA Link Relations registry [7]. I am not even sure which set of topological relations we should be recommending? GeoSPARQL has me somewhat confused with "Simple Features Relation", "Egenhofer Relation" and "RCC8 Relation". Then there's D9-EIM too ...

Can someone provide me some worked examples using the preferred set of topological relationships?

We also need to illustrate use of _directional_ (e.g. "left", "in front of" and "astern") and _distance_ relations (e.g. "at", "nearby" and "far away"). I don't know of any formalised vocabulary for expressing these things. If there is one, should we be seeking to add these to the IANA Link Relations registry too?

Again, worked examples requested! If you can related them to an urban environment / flooding scenario all the better. (e.g. someone might assert "the flooding is near my house")

Finally, we also need to show people how to express "fuzzy" spatial things. Examples we have elsewhere in the BP doc are "the American West" and "Renaissance Italy". These are spatial things were there is not general agreement about the exact geographic extent, so it is not possible to use a geometry to describe it. What is the best way to describe things like this? Should we use spatial relations e.g. "downtown" _contains_ city districts A, C, D, and G (because "everyone" agrees this) - but we're not saying it's exact geometry because it's a colloquial term used by citizens of our fictional Nieuwhaven.

Again, I'd like to see a worked example.


There's a lot of questions wrapped up in this email. I'm looking for help to resolve them ... preferably with someone in the WG taking the lead to coordinate a response.

I'm also aware that we need to avoid an RDF bias, so it would be good to have examples in other formats too.

Volunteers, please step forward!

Thanks in advance. Jeremy

[1]: http://w3c.github.io/sdw/bp/#bp-expr-geo

[2]: http://w3c.github.io/sdw/bp/#describe-geometry

[3]: http://w3c.github.io/sdw/bp/#relative-position

[4]: http://w3c.github.io/sdw/bp/#spatial-relations

[5]: https://github.com/ISO-TC211/HMMG

[6]: http://inspire.ec.europa.eu/documents/Data_Specifications/INSPIRE_DataSpecification_TN_v3.2.pdf

[7]: http://www.iana.org/assignments/link-relations/link-relations.xhtml


Ed Parsons FRGS
Geospatial Technologist, Google

Google Voice +44 (0)20 7881 4501<tel:%2B44%20%280%2920%207881%204501>
www.edparsons.com<http://www.edparsons.com/> @edparsons
Received on Friday, 2 September 2016 01:28:53 UTC

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