And W3C has finalized stabilized xlink in terms of an official document and
position statement.
Carl
----- Original Message -----
From: Woolf, Andrew (STFC,RAL,ESC)
To: Peter Baumann
Cc: Robin, Alexandre ; Max Martinez ; Ben Domenico ; Unidata Techies ;
Unidata GALEON ; Carl Reed ; wcs-2.0.swg
Sent: Thursday, August 20, 2009 8:41 AM
Subject: RE: GML coverages / xlink
gml:File is one of the most ill-conceived ideas I've seen. I've also never
seen it being used. The semantics are completely uncontrolled - if someone gave
me a GML using it, I wouldn't know what to do. xlink semantics are
well-defined, and the proposed usage gives you (almost) no choice but to
interpret things correctly.
From: Peter Baumann [mailto:p.baumann@xxxxxxxxxxxxxxxxxxxx]
Sent: 20 August 2009 15:28
To: Woolf, Andrew (STFC,RAL,ESC)
Cc: Robin, Alexandre; Max Martinez; Ben Domenico; Unidata Techies; Unidata
GALEON; Carl Reed; wcs-2.0.swg
Subject: Re: GML coverages / xlink
Andrew-
looks nice, but how is the relation to the gml:File choice which provides for
a file embedding alternative as well? Is this redundant functionality?
-Peter
Woolf, Andrew (STFC,RAL,ESC) wrote:
<RectifiedGridCoverage id="tos_O1_2001-2002">
<domainSet>
<RectifiedGrid dimension="3" id="tos_O1_2001-2002.domain">
<limits>
<GridEnvelope>
<low>0 0 0</low>
<high>23 169 179</high>
</GridEnvelope>
</limits>
<axisLabels>x y t</axisLabels>
<origin>
<Point id="tos_O1_2001-2002.domain.origin"
srsName="urn:x-ogc:def:crs:badc:TimeLatLon:2001-01-01:1d">
<pos>-79.5 1 1</pos>
</Point>
</origin>
<offsetVector
srsName="urn:x-ogc:def:crs:badc:TimeLatLon:2001-01-01:1d">1 0 0</offsetVector>
<offsetVector
srsName="urn:x-ogc:def:crs:badc:TimeLatLon:2001-01-01:1d">0 1 0</offsetVector>
<offsetVector
srsName="urn:x-ogc:def:crs:badc:TimeLatLon:2001-01-01:1d">0 0 2</offsetVector>
</RectifiedGrid>
</domainSet>
<rangeSet>
<ValueArray gml:id="tos_O1_2001-2002.range">
<valueComponent
xlink:href="http://www.unidata.ucar.edu/software/netcdf/examples/tos_O1_2001-2002.nc#tos";
xlink:role="urn:mimetype:application/x-netcdf"
xlink:arcrole="QuantityList">
<QuantityList uom="K"/>
</valueComponent>
</ValueArray>
</rangeSet>
</RectifiedGridCoverage>
(The referenced CRS is a composite using a TM_CoordinateSystem
(gml:TimeCoordinateSystem) for time, with origin 2001-01-01 and interval 'one
day'.)
Our current CR 07-112 will enable analogous use of CF-netCDF files using
'auxiliary coordinate variables' for a gml:ReferenceableGrid.
Cheers,
Andrew
From: Peter Baumann [mailto:p.baumann@xxxxxxxxxxxxxxxxxxxx]
Sent: 20 August 2009 10:50
To: Woolf, Andrew (STFC,RAL,ESC)
Cc: Robin, Alexandre; Max Martinez; Ben Domenico; Unidata Techies; Unidata
GALEON; Carl Reed; wcs-2.0.swg
Subject: GML coverages / xlink (was: Re: [WCS-2.0.swg] CF-netCDF standards
initiatives)
Andrew-
I anyway wanted to contact you on the xlink question.
Your approach as presented at the Boston TC meeting I consider the missing
link for WCS: we consider coverages delivered as a manifest (XML) and one or
more encoded files, referenced from the manifest. It seems like your approach
allows to mimic this in GML. Is that correct?
As we currently are seriously considering adopting GML for the WCS 2.0
coverage model such a facility is of high importance to us.
-Peter
PS: this might also resolve the dispute of this thread: GML coverages can
well reference a netCDF file then, can't they?
Woolf, Andrew (STFC,RAL,ESC) wrote:
I'd say the same thing about GML - it's already possible to use GML to
provide a canonical encoding linked to an underlying conceptual model AND xlink
to netCDF for the actual content.
Andrew
From: wcs-2.0.swg-bounces+andrew.woolf=stfc.ac.uk@xxxxxxxxxxxxxxxxxxxxxxxx
[mailto:wcs-2.0.swg-bounces+andrew.woolf=stfc.ac.uk@xxxxxxxxxxxxxxxxxxxxxxxx]
On Behalf Of Robin, Alexandre
Sent: 20 August 2009 09:16
To: Max Martinez; Ben Domenico; Peter Baumann
Cc: Unidata Techies; Unidata GALEON; Carl Reed; wcs-2.0.swg
Subject: Re: [WCS-2.0.swg] CF-netCDF standards initiatives
FYI,
SWE Common can serve to send very efficiently packaged datasets (binary,
compressed binary) just like NetCDF does while providing robust metadata
describing the datasets.
These datasets can be N-D grid coverages, discrete coverages, or any other
kind of sensor observations or model results.
The point for us to build SWE Common rather than just reusing NetCDF was to
support efficient random access in huge datasets and real time streaming data
(which NetCDF is not designed for) with a single model.
Both cases are supported and I am pretty sure we can generate a SWE Common
encoded binary stream that is byte-to-byte compatible with the data section of
a NetCDF file.
Developing a module for the NetCDF API dealing with SWE Common would be quite
trivial thanks to the harmonization work we have already done.
Regards,
-------------------------------------------------
Alexandre Robin
Spot Image, Web and E-Business
Tel: +33 (0)5 62 19 43 62
Fax: +33 (0)5 62 19 43 43
http://www.spotimage.com
Before printing, think about the environment
------------------------------------------------------------------------------
De : Robin, Alexandre
Envoyé : jeudi 20 août 2009 10:01
À : 'Max Martinez'; Ben Domenico; Peter Baumann
Cc : Unidata Techies; Unidata GALEON; wcs-2.0.swg; 'Carl Reed'
Objet : RE: [WCS-2.0.swg] CF-netCDF standards initiatives
Ben,
I hope we don't have to define a NEW standard but rather work with you to see
how we can treat your use cases with SWE Common (which already incorporates
some NetCDF concepts and is VERY close to NcML).
I already looked at the issue and writing a converter (even the 'on the fly'
kind) between the two formats should be no problem at all.
Bringing legacy formats (be them pseudo-defacto standards of a community)
into OGC is NOT going to help interoperability across domains.
Regards,
-------------------------------------------------
Alexandre Robin
Spot Image, Web and E-Business
Tel: +33 (0)5 62 19 43 62
Fax: +33 (0)5 62 19 43 43
http://www.spotimage.com
Before printing, think about the environment
------------------------------------------------------------------------------
De :
wcs-2.0.swg-bounces+alexandre.robin=spotimage.fr@xxxxxxxxxxxxxxxxxxxxxxxx
[mailto:wcs-2.0.swg-bounces+alexandre.robin=spotimage.fr@xxxxxxxxxxxxxxxxxxxxxxxx]
De la part de Max Martinez
Envoyé : jeudi 20 août 2009 03:19
À : Ben Domenico; Peter Baumann
Cc : Unidata Techies; Unidata GALEON; wcs-2.0.swg
Objet : Re: [WCS-2.0.swg] CF-netCDF standards initiatives
Ben,
What exactly is an "OGC binary encoding standard"? Is CF-netCDF attempting to
be the first of its kind or are there other examples?
Max
------------------------------------------------------------------------------
From: wcs-2.0.swg-bounces+max.martinez=erdas.com@xxxxxxxxxxxxxxxxxxxxxxxx
[mailto:wcs-2.0.swg-bounces+max.martinez=erdas.com@xxxxxxxxxxxxxxxxxxxxxxxx] On
Behalf Of Ben Domenico
Sent: Wednesday, August 19, 2009 1:19 PM
To: Peter Baumann
Cc: Unidata Techies; Unidata GALEON; wcs-2.0.swg
Subject: [WCS-2.0.swg] CF-netCDF standards initiatives
Hello,
Some confusion has resulted from the fact that we are pursuing two parallel
efforts at standardizing CF-netCDF within the OGC.
The first initiative began a few years ago. The goal is to establish
CF-netCDF as an extension standard for WCS encoding of data in binary form.
Stefano Nativi just sent out an email announcing the latest revision of the
proposed "discussion paper" on that topic. This will be discussed and
hopefully voted on at the September/October TC meeting.
At the same time, we have a new initiative to establish CF-netCDF as a
separate OGC binary encoding standard. This approach will result in a
binary encoding which can be used with different access protocols, e.g., WFS or
SOS as well as WCS. Of course, in the long run, our objective is to tie the
two approaches together, but we do not want to impede progress on either right
now by making them formally interdependent. A very rough draft of the core
standard for CF-netCDF is on the GALEON wiki at:
http://sites.google.com/site/galeonteam/Home/cf-netcdf-candidate-standard
As you can see, the draft for the OGC core is based on the NASA Earth Science
Data System standard (NASA ESDS-RFC-011v1.00). We hope to have this candidate
standard in the proper OGC template form by the September/October TC and will
have an ad-hoc session at which we plan to establish a SWG. Since there is
already a large community of practice, endorsement by other standards groups
(NASA and NOAA in the US), and solid reference implementations, we hope to move
forward quickly with this standard.
We would very much like to have as many liaisons as possible between the WCS
and CF-netCDF working groups to ensure that they are kept in harmony.
-- Ben
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-- Dr. Peter Baumann - Professor of Computer Science, Jacobs University Bremen
www.faculty.jacobs-university.de/pbaumann mail:
p.baumann@xxxxxxxxxxxxxxxxxxxx tel: +49-421-200-3178, fax: +49-421-200-493178
- Executive Director, rasdaman GmbH Bremen (HRB 147737) www.rasdaman.com,
mail: baumann@xxxxxxxxxxxx tel: 0800-rasdaman, fax: 0800-rasdafax, mobile:
+49-173-5837882"A brilliant idea is a job halfdone."
--
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-- Dr. Peter Baumann - Professor of Computer Science, Jacobs University Bremen
www.faculty.jacobs-university.de/pbaumann mail:
p.baumann@xxxxxxxxxxxxxxxxxxxx tel: +49-421-200-3178, fax: +49-421-200-493178
- Executive Director, rasdaman GmbH Bremen (HRB 147737) www.rasdaman.com,
mail: baumann@xxxxxxxxxxxx tel: 0800-rasdaman, fax: 0800-rasdafax, mobile:
+49-173-5837882"A brilliant idea is a job halfdone."
--
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