RE: Princples...

Hi Lewis,


1.       Well, the obvious example is any THREDDS server. These give access into a data cube using the URI that ‘knows’ the internal structure of the (NetCDF) data. The interfaces are currently all meteorology specific, though I think that there is current work to make them OGC compliant in some sense.



2.       ECWMF’s MARS (Meteorological Archive & Retrieval System) does something similar, but in advance, by only storing ‘atomic’ fields (one parameter, one time, one level, quasi horizontal grid of data). The user uses the MARS retrieval language to specify and request a subset.


3.       We did a prototype tile server that delivered gridded wind data to AR mobile devices, but the hypercube has to be sliced and diced into ‘atomic’ fields to be scalable and cacheable nearer the client.



4.       I think the DAACs have the same problem – having chosen a serialisation for a storage granule (I think that that is the correct term), somebody will always want to retrieve fields along the ‘diagonal’ requiring many storage granules


Hence my interest in a data tile spec in OGC.

HTH, Chris

From: Mcgibbney, Lewis J (398M) [mailto:Lewis.J.Mcgibbney@jpl.nasa.gov]
Sent: Thursday, April 23, 2015 5:28 PM
To: Little, Chris; thiago.avila@ic.ufal.br; Kerry.Taylor@csiro.au
Cc: public-sdw-wg@w3.org
Subject: Re: Princples...

Hi Chris,
Can you show us a concrete example if one exists? Are slices of the data available anywhere? I am intrigued.
In JPL’s PO.DAAC (Physical Oceanographic Data Active Archive Centre) there are a number of solutions aimed at improving/lowering the barrier to data access
http://podaac.jpl.nasa.gov/dataaccess


In the use case you mention, I would imagine it would be possible to reference and hence locate then extract geo-referenced granules for some given parameter(s).
We do that in PO.DAAC in a number of ways
http://podaac.jpl.nasa.gov/ws/


Example usage for extracting granules


Example 1: Extract granule with Dataset ID = PODAAC-QSX25-L2B02, shortName of QSCAT_LEVEL_2B_V2, granuleName QS_S2B54295.20093261514, offset the region contained within -135.0 W, 30.0 N, -120.0 W, 40.0 N, have it save as netcdf.
http://podaac.jpl.nasa.gov/ws/extract/granule?shortName=ASCATA-L2-25km&granuleName=ascat_20130719_230600_metopa_35024_eps_o_250_2200_ovw.l2.nc&bbox=-180,-90,180,90&format=netcdf


If this is totally off, then excuse me. If it contributes to conversation then I would be glad to hear more about your Meteorology use case here as I have little to do with data from this domain.
Lewis

Dr. Lewis John McGibbney Ph.D., B.Sc., MAGU
Engineering Applications Software Engineer Level 2
Computer Science for Data Intensive Systems Group 398M
Jet Propulsion Laboratory
California Institute of Technology
4800 Oak Grove Drive
Pasadena, California 91109-8099
Mail Stop : 158-256C
Tel:  (+1) (818)-393-7402
Cell: (+1) (626)-487-3476
Fax:  (+1) (818)-393-1190
Email: lewis.j.mcgibbney@jpl.nasa.gov<mailto:lewis.j.mcgibbney@jpl.nasa.gov>

           [cid:image001.png@01D081D0.0EB3A7E0]

 Dare Mighty Things

From: <Little>, Chris <chris.little@metoffice.gov.uk<mailto:chris.little@metoffice.gov.uk>>
Date: Thursday, April 23, 2015 at 1:31 AM
To: "thiago.avila@ic.ufal.br<mailto:thiago.avila@ic.ufal.br>" <thiago.avila@ic.ufal.br<mailto:thiago.avila@ic.ufal.br>>, "Kerry.Taylor@csiro.au<mailto:Kerry.Taylor@csiro.au>" <Kerry.Taylor@csiro.au<mailto:Kerry.Taylor@csiro.au>>
Cc: "public-sdw-wg@w3.org<mailto:public-sdw-wg@w3.org>" <public-sdw-wg@w3.org<mailto:public-sdw-wg@w3.org>>
Subject: RE: Princples...
Resent-From: <public-sdw-wg@w3.org<mailto:public-sdw-wg@w3.org>>
Resent-Date: Thursday, April 23, 2015 at 1:31 AM

Thiago, Kerry

Meteorology has use cases where linked data/RDF/triple stores/etc are not appropriate. Take a large (~1TByte) 5 dimensional data cube identified by only one URI/link, of one parameter, say the vector wind speed and direction,  and it is replaced every 6 hours. The data is all geo-referenced, and users wish to extract much more manageable subsets.

At this stage, I am not sure whether  all practices of W3C Best Practices for Publishing Linked Data<http://www.w3.org/TR/ld-bp/>
are helpful.

Chris

From: Kerry.Taylor@csiro.au<mailto:Kerry.Taylor@csiro.au> [mailto:Kerry.Taylor@csiro.au]
Sent: Thursday, April 23, 2015 8:01 AM
To: thiago.avila@ic.ufal.br<mailto:thiago.avila@ic.ufal.br>; public-sdw-wg@w3.org<mailto:public-sdw-wg@w3.org>
Subject: RE: Princples...

Thiago,
I  do not think we should be reiterating those practices – that is not our job. It would be unfortunate if we were contradictory, though.

In our case, it is not obvious to what extent this group is focusing on linked data, or not, and I think our views in the group  may be divergent.

The UCR document should be “A document setting out the range of problems that the working groups are trying to solve.”  So in that context  I thought to bring up the question ( deliberately phrased in the form that reflects my point of view!).

Kerry

From: Thiago José Tavares Ávila [mailto:thiago.avila@ic.ufal.br]
Sent: Thursday, 23 April 2015 10:32 AM
To: public-sdw-wg@w3.org<mailto:public-sdw-wg@w3.org>
Subject: Re: Princples...

Hello Kerry,

For 5th principle, Does geospatial data must follow all practices of W3C Best Practices for Publishing Linked Data<http://www.w3.org/TR/ld-bp/> ?

Regards. Thiago

2015-04-19 23:26 GMT-03:00 <Kerry.Taylor@csiro.au<mailto:Kerry.Taylor@csiro.au>>:
Here's 2 suggestions ( that may need improvement).

No 5. That community good practice for 5 star linked data be followed, including the use of so-called cool uris and  ontology annotations ( references need to be attached)

No 6. That ontologies  conform (" are valid" ? check) to the language of  owl2 dl.
(The latter is important for spatial and temporal reasoning.)

No 7. ( perhaps number  0) That these principles are aimed specifically at data published in RDF but where appropriate may also apply to other spatial data published on the web.


Kerry

On 20 Apr 2015, at 8:17 am, "John Machin" <john.machin@abs.gov.au<mailto:john.machin@abs.gov.au>> wrote:

Hi Ed, Andreas,

I like the proposed principles so far.

Based on some of the comments in the last call, I wonder if we have to have a principle related to keeping the practices up to date?

I realise that this might over-commitment from a WG with a specified lifespan but if maintaining currency is a principle then the two sponsor organisations may be encouraged to reconvene WGs to review and update the Best Practices periodically.

Cheers,
--
John Machin

<graycol.gif>Andreas Harth ---18/04/2015 05:57:59 AM---Hi Ed, On 2015-04-16 14:10, Ed Parsons wrote:

From: Andreas Harth <harth@kit.edu<mailto:harth@kit.edu>>
To: <public-sdw-wg@w3.org<mailto:public-sdw-wg@w3.org>>,
Date: 18/04/2015 05:57 AM
Subject: Re: Princples...

________________________________



Hi Ed,

On 2015-04-16 14:10, Ed Parsons wrote:
> So to start the ball rolling....
>
> Princple No.1 : The linkabilty of Geospatial Information published on
> the web should be improved.
>
[...]
>
> Princple No.2 : We will not reinvent
>
[...]
>
> Feel free to add to these, develop more ... when we reach a level of
> agreement I will transfer them over to the wiki

How about the following?

Principle No.3 : Best Practices have to be visible.

We will link to at least one (or two, three?) publicly available
example(s) of a non-toy dataset that follows the best practice.

Cheers,
Andreas.