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RE: Working list of BP requirements identified during the SDW WG f2f

From: <Simon.Cox@csiro.au>
Date: Tue, 17 Mar 2015 20:40:52 +0000
To: <frans.knibbe@geodan.nl>, <public-sdw-wg@w3.org>
Message-ID: <2A7346E8D9F62D4CA8D78387173A054A600DD3AA@exmbx04-cdc.nexus.csiro.au>
>>> Firstly, the OGC reference systems do have URIs, but they are not dereferencable to data describing the reference systems.
>> Did you try clicking on the link above? It goes to an (XML) document defining the CRS.
> No, I did not click the link. Sorry. But I did now. If I recall correctly, a while ago the link did not return data. But now it does. It is good to see this kind of progress!

It has been running fine for about 3 years now. It is unfortunate to read untested, incorrect assertions made about availability of resources, and the stability of the services that OGC provides to the community, particularly on this forum.

From: Frans Knibbe | Geodan [mailto:frans.knibbe@geodan.nl]
Sent: Wednesday, 18 March 2015 7:13 AM
To: public-sdw-wg@w3.org
Subject: Re: Working list of BP requirements identified during the SDW WG f2f

On 2015-03-17 14:49, Joshua Lieberman wrote:



But more importantly, I think we will have to decide not to view a requirement like 'there should be a best practice for minting URIs of spatial phenomena' as something we should busy ourselves with. I can think of no reason to see the URI minting problem as something that is inherently spatial, temporal or spatiotemporal. Besides that, there already are some good guidelines on minting URIs out there.

It isn't necessarily a critical for a useful URI, but space-time is a domain and that suggests some value in organizing the URI's that explicitly reference features in it. Otherwise multiple unrelated URI's are created that resolve to the same location or feature with resultant overhead to assert their relationships. This is especially related to the use case for authoritative framework data.
I am not sure I understand what you mean. Could you please give an example (real or imaginary)?




1.8 The OGC URI scheme includes common CRS. Try http://www.opengis.net/def/crs/EPSG/0/4326 for example. I trust that one of the OGC people in the meeting mentioned this?

I am fairly sure that this was mentioned, and if not it is good to see it mentioned here. Two things came up that indicate that we might want to go a step further: Firstly, the OGC reference systems do have URIs, but they are not dereferencable to data describing the reference systems. Secondly, it would be good to have some best practice for the description of reference systems in general, not just earth-based reference systems.

Did you try clicking on the link above? It goes to an (XML) document defining the CRS.
No, I did not click the link. Sorry. But I did now. If I recall correctly, a while ago the link did not return data. But now it does. It is good to see this kind of progress!



I noticed an interesting parallel for time and space there: In both cases the regular reference systems are fairly well covered by standards (earth based reference systems for space, Gregorian calendar for time), but less common reference systems are not easy to use in a standardized way.

Generally the "less common" ones are complicated because they cover a wide range of complicated situations, such as the SEDRIS SRM (
ISO/IEC 18026:2006). They are standardized, but used mostly when they can't be avoided.

There are reference systems that are simple (such as 2D cartesian), but are uncommon because of an uncommon (unique) point of origin. For example, I could state that I see a White-rumped sandpiper at ten o'clock (in which case my present position and orientation is the origin). Or I could say that Ed's keys are in his bedroom. Also a Building Information Model (BIM) could have simple but unique reference system because it has its own point of origin (the corner of a particular land parcel for example).

I think that in the domain of time similar (simple but in some way unique) reference systems can be used. I understand that it is a common practice to date archaeological finds in Egypt using the list of kings. That list by itself is simple, it is a list of king names (the related Gregorian dates could change as scientific knowledge progresses). But a find somewhere in the middle east could be dated by another king list (Sumerian kings, Assyrian kings,....).

Greetings,
Frans



Regards,
Frans


Simon



-----Original Message-----

From: Andrea Perego [mailto:andrea.perego@jrc.ec.europa.eu]

Sent: Monday, 16 March 2015 5:03 PM

To: SDW WG

Subject: Working list of BP requirements identified during the SDW WG f2f



Dear all,



I've extracted from the minutes of the BP deliverable group a preliminary list of requirements, concerning the discussed use cases (1-24).



You can find it on the wiki:



https://www.w3.org/2015/spatial/wiki/BP_Requirements



Please have a look, and modify / extend it as you see fit.



Cheers,



Andrea



--

Andrea Perego, Ph.D.

Scientific / Technical Project Officer

European Commission DG JRC

Institute for Environment & Sustainability Unit H06 - Digital Earth & Reference Data Via E. Fermi, 2749 - TP 262

21027 Ispra VA, Italy



https://ec.europa.eu/jrc/



----

The views expressed are purely those of the writer and may not in any circumstances be regarded as stating an official position of the European Commission.





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Received on Tuesday, 17 March 2015 20:41:42 UTC

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