Re: [galeon] [WCS-2.0.swg] CF-netCDF standards initiatives

Hi John,

 

SWE Common has been around for about 3 years at OGC but was part of the 
SensorML 1.0 specification 
<http://portal.opengeospatial.org/files/?artifact_id=21273>  which made it 
pretty much invisible.

Version 2.0 of SWE Common is in the works now and will be a separate 
specification thus allowing it to be used in a standalone manner.

 

The scope of SWE Common (the long version is actually SWE Common Data Model so 
you can see that it relates directly to Unidata CDM) is the description (in 
XML) of datasets structure, semantics, units, etc... as well as encodings for 
the data itself (in XML, ASCII and binary). Objects called "DataArray" which 
dimensions can be robustly defined are used to model N-D coverages. As I said 
earlier the binary encoding of the data itself can be made byte-to-byte 
compatible with the data section of a NetCDF file.

 

The O&M (Observation and Measurements) specification v1.0 also makes use of SWE 
Common to describe observation result streams.

You can find simple examples such as a weather data stream 
<http://schemas.opengis.net/om/1.0.0/examples/weatherObservation.xml>  with the 
O&M schemas online at http://schemas.opengis.net/om/1.0.0/examples.

However please be aware that not all O&M examples use SWE Common...

 

I can point you to more complex examples such as video streams, aircraft 
imagery streams and satellite imagery if you want.

 

I would also recommend that somebody in your group join the SWE Common SWG at 
OGC so we can join effort for the streaming format you're trying to define.

 

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 <http://www.spotimage.com/>  

Before printing, think about the environment

 

 

> -----Message d'origine-----

> De : John Caron [mailto:caron@xxxxxxxxxxxxxxxx]

> Envoyé : jeudi 20 août 2009 17:42

> Cc : Robin, Alexandre; Unidata GALEON; wcs-2.0.swg

> Objet : Re: [galeon] [WCS-2.0.swg] CF-netCDF standards initiatives

> 

> Hi Alexandre:

> 

> This is the first Ive heard of SWE Common (which doesnt mean much since

> I havent followed the SWE efforts closely). Is it possible to get more

> information about the data model and encoding? Unidata is also working

> on a streaming format, and it would be interesting to see how the two

> efforts compare. Also how SWE Common relates/compares to NcML.

> 

> Thanks,

> 

> John Caron

> Unidata

> 

> 

> 

> > *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

> >