[CF-metadata] Explanation of mass_concentration_of_water_vapor_in_air ?
Dear all, Is it possible to make suggestion for the small text describing the names in the CF standard name table ? I yes, I would suggest to modify the text describing mass_concentration_of_water_vapor_in_air. The beginning of the sentence is clear, and anybody is able to understand it (Mass concentration means mass per unit volume). But I think that it may be a valuable addition to write that : the usual name of this quantity in Atmospheric Sciences in absolute humidity. I believe that this would help people searching the standard name table. Bruno. References to this definition, if needed : 1) WORLD METEOROLOGICAL ORGANIZATION, INSTRUMENTS AND OBSERVING METHODS REPORT No. 86 TRAINING MATERIAL ON METROLOGY AND CALIBRATION http://www.wmo.int/pages/prog/www/IMOP/publications/IOM-19-Synoptic-AWS.pdf 2) http://nsidc.org/arcticmet/glossary/absolute_humidity.html -- Bruno PIGUET Mèl : bruno.pig...@meteo.fr | GAME : URA CNRS METEO-FRANCE Tel : +33 (0)5 61 07 96 59 | CNRM/GMEI/TRAMM Fax : +33 (0)5 61 07 96 27 | 42 Av. G. Coriolis Sec : +33 (0)5 61 07 96 63 | 31057 TOULOUSE cedex 1 signature.asc Description: This is a digitally signed message part ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
Re: [CF-metadata] Web reference to a standard name?
We have tried to get standard URIs for CF concepts, but the effort bogged down. As for standard names, MMI established a set of URIs at http://marinemetadata.org/cf but has not been keeping up to date. I have written a XSL transform at http://iridl.ldeo.columbia.edu/ontologies/xslt/.cfsn2rdf.xsl that can be applied to http://cf-pcmdi.llnl.gov/documents/cf-standard-names/standard-name-table/16/cf-standard-name-table.xml to generate an up-to-date version, e.g. xsltproc http://iridl.ldeo.columbia.edu/ontologies/xslt/.cfsn2rdf.xsl http://cf-pcmdi.llnl.gov/documents/cf-standard-names/standard-name-table/16/cf-standard-name-table.xml On the other hand, Roy has created opaque URIs for standard names at http://vocab.ndg.nerc.ac.uk/list/P07/9 contains all the Standard Names that have ever been published, including names that have been aliased http://vocab.ndg.nerc.ac.uk/list/P071/9 contains the Standard Names that are currently valid (i.e. those that have not been deprecated through aliasing) http://vocab.ndg.nerc.ac.uk/list/P072/9 contains the Standard Names that have been deprecated through aliasing The mapping between deprecates and their replacement aliases my be obtained through the following API call http://vocab.ndg.nerc.ac.uk/axis2/services/vocab/getMap?subjectList=http://vocab.ndg.nerc.ac.uk/list/P072/currentpredicate=255objectList=http://vocab.ndg.nerc.ac.uk/list/P071/currentinference=false he changes them with each version, so it is both more definitive and harder to use. It is also pure SKOS, so one needs to add structure to actually connect it with a CF-described dataset. I plan to write out a map between the two, so that I can use his relationships between CF standard_names, but I do not have it yet. Additional information and ontologies describing the CF structure both as attributes and conceptually are available at http://iridl.ldeo.columbia.edu/ontologies/, including the connections between the standard_name ontologies and the CF structure. Benno On Mon, Dec 13, 2010 at 9:22 AM, Dominic Lowe dominic.l...@stfc.ac.uk wrote: Hello all, What's the current CF recommended scheme for referencing a standard name on the web? (either by URL or URN). I know about the vocab server and the xml/html online versions and could choose to use URLs to point to items in any of these but is there a definitive pattern that should be used? (or at least a best practice that should be encouraged?). Much appreciated, Dominic -- Scanned by iCritical. ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata -- Dr. M. Benno Blumenthal be...@iri.columbia.edu International Research Institute for climate and society The Earth Institute at Columbia University Lamont Campus, Palisades NY 10964-8000 (845) 680-4450 ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
Re: [CF-metadata] Web reference to a standard name?
Hi Benno, That's a pretty thorough overview of the current position. One minor point is that the URIs you give from my system serve version 9 - not the current version. Replace the '9' by 'current' to get the latest version e.g. http://vocab.ndg.nerc.ac.uk/list/P071/9 http://vocab.ndg.nerc.ac.uk/list/P071/http://vocab.ndg.nerc.ac.uk/list/P071/currentcurrent . Cheers, Roy. From: cf-metadata-boun...@cgd.ucar.edu [cf-metadata-boun...@cgd.ucar.edu] On Behalf Of Benno Blumenthal [be...@iri.columbia.edu] Sent: 13 December 2010 15:25 To: Dominic Lowe Cc: cf-metadata@cgd.ucar.edu Subject: Re: [CF-metadata] Web reference to a standard name? We have tried to get standard URIs for CF concepts, but the effort bogged down. As for standard names, MMI established a set of URIs at http://marinemetadata.org/cf but has not been keeping up to date. I have written a XSL transform at http://iridl.ldeo.columbia.edu/ontologies/xslt/.cfsn2rdf.xsl that can be applied to http://cf-pcmdi.llnl.gov/documents/cf-standard-names/standard-name-table/16/cf-standard-name-table.xml to generate an up-to-date version, e.g. xsltproc http://iridl.ldeo.columbia.edu/ontologies/xslt/.cfsn2rdf.xsl http://cf-pcmdi.llnl.gov/documents/cf-standard-names/standard-name-table/16/cf-standard-name-table.xml On the other hand, Roy has created opaque URIs for standard names at http://vocab.ndg.nerc.ac.uk/list/P07/9 contains all the Standard Names that have ever been published, including names that have been aliased http://vocab.ndg.nerc.ac.uk/list/P071/9 contains the Standard Names that are currently valid (i.e. those that have not been deprecated through aliasing) http://vocab.ndg.nerc.ac.uk/list/P072/9 contains the Standard Names that have been deprecated through aliasing The mapping between deprecates and their replacement aliases my be obtained through the following API call http://vocab.ndg.nerc.ac.uk/axis2/services/vocab/getMap?subjectList=http://vocab.ndg.nerc.ac.uk/list/P072/currentpredicate=255objectList=http://vocab.ndg.nerc.ac.uk/list/P071/currentinference=false he changes them with each version, so it is both more definitive and harder to use. It is also pure SKOS, so one needs to add structure to actually connect it with a CF-described dataset. I plan to write out a map between the two, so that I can use his relationships between CF standard_names, but I do not have it yet. Additional information and ontologies describing the CF structure both as attributes and conceptually are available at http://iridl.ldeo.columbia.edu/ontologies/, including the connections between the standard_name ontologies and the CF structure. Benno On Mon, Dec 13, 2010 at 9:22 AM, Dominic Lowe dominic.l...@stfc.ac.ukmailto:dominic.l...@stfc.ac.uk wrote: Hello all, What's the current CF recommended scheme for referencing a standard name on the web? (either by URL or URN). I know about the vocab server and the xml/html online versions and could choose to use URLs to point to items in any of these but is there a definitive pattern that should be used? (or at least a best practice that should be encouraged?). Much appreciated, Dominic -- Scanned by iCritical. ___ CF-metadata mailing list CF-metadata@cgd.ucar.edumailto:CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata -- Dr. M. Benno Blumenthal be...@iri.columbia.edumailto:be...@iri.columbia.edu International Research Institute for climate and society The Earth Institute at Columbia University Lamont Campus, Palisades NY 10964-8000 (845) 680-4450 -- This message (and any attachments) is for the recipient only NERC is subject to the Freedom of Information Act 2000 and the contents of this email and any reply you make may be disclosed by NERC unless it is exempt from release under the Act. Any material supplied to NERC may be stored in an electronic records management system.___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
Re: [CF-metadata] Web reference to a standard name?
Hello Dominic and all, MMI maintains an SKOS-based representation of the CF standard names at the MMI Ontology Registry and Repository (ORR): http://mmisw.org/ont/cf/parameter In your browser, this URL will open the ontology in the ORR Portal. You can click the Versions button to see a history of the versions we have at the ORR. You can use content negotiation or an extension to request a particular format, eg: http://mmisw.org/ont/cf/parameter.rdf http://mmisw.org/ont/cf/parameter.n3 You can find more details about the SKOS representation, mappings, Web resolution of terms, and SPARQL queries involving the CF ontology at: http://marinemetadata.org/orrcf . We would appreciate much any feedback to improve this service and the documentation. Best regards, Carlos On Mon, Dec 13, 2010 at 8:10 AM, Lowry, Roy K. r...@bodc.ac.uk wrote: Hi Benno, That's a pretty thorough overview of the current position. One minor point is that the URIs you give from my system serve version 9 - not the current version. Replace the '9' by 'current' to get the latest version e.g. http://vocab.ndg.nerc.ac.uk/list/P071/9 http://vocab.ndg.nerc.ac.uk/list/P071/http://vocab.ndg.nerc.ac.uk/list/P071/currentcurrent . Cheers, Roy. -- *From:* cf-metadata-boun...@cgd.ucar.edu [cf-metadata-boun...@cgd.ucar.edu] On Behalf Of Benno Blumenthal [be...@iri.columbia.edu] *Sent:* 13 December 2010 15:25 *To:* Dominic Lowe *Cc:* cf-metadata@cgd.ucar.edu *Subject:* Re: [CF-metadata] Web reference to a standard name? We have tried to get standard URIs for CF concepts, but the effort bogged down. As for standard names, MMI established a set of URIs at http://marinemetadata.org/cf but has not been keeping up to date. I have written a XSL transform at http://iridl.ldeo.columbia.edu/ontologies/xslt/.cfsn2rdf.xsl that can be applied to http://cf-pcmdi.llnl.gov/documents/cf-standard-names/standard-name-table/16/cf-standard-name-table.xml to generate an up-to-date version, e.g. xsltproc http://iridl.ldeo.columbia.edu/ontologies/xslt/.cfsn2rdf.xsl http://cf-pcmdi.llnl.gov/documents/cf-standard-names/standard-name-table/16/cf-standard-name-table.xml On the other hand, Roy has created opaque URIs for standard names at http://vocab.ndg.nerc.ac.uk/list/P07/9 contains all the Standard Names that have ever been published, including names that have been aliased http://vocab.ndg.nerc.ac.uk/list/P071/9 contains the Standard Names that are currently valid (i.e. those that have not been deprecated through aliasing) http://vocab.ndg.nerc.ac.uk/list/P072/9 contains the Standard Names that have been deprecated through aliasing The mapping between deprecates and their replacement aliases my be obtained through the following API call http://vocab.ndg.nerc.ac.uk/axis2/services/vocab/getMap?subjectList=http://vocab.ndg.nerc.ac.uk/list/P072/currentpredicate=255objectList=http://vocab.ndg.nerc.ac.uk/list/P071/currentinference=false he changes them with each version, so it is both more definitive and harder to use. It is also pure SKOS, so one needs to add structure to actually connect it with a CF-described dataset. I plan to write out a map between the two, so that I can use his relationships between CF standard_names, but I do not have it yet. Additional information and ontologies describing the CF structure both as attributes and conceptually are available at http://iridl.ldeo.columbia.edu/ontologies/, including the connections between the standard_name ontologies and the CF structure. Benno On Mon, Dec 13, 2010 at 9:22 AM, Dominic Lowe dominic.l...@stfc.ac.uk wrote: Hello all, What's the current CF recommended scheme for referencing a standard name on the web? (either by URL or URN). I know about the vocab server and the xml/html online versions and could choose to use URLs to point to items in any of these but is there a definitive pattern that should be used? (or at least a best practice that should be encouraged?). Much appreciated, Dominic -- Scanned by iCritical. ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata -- Dr. M. Benno Blumenthal be...@iri.columbia.edu International Research Institute for climate and society The Earth Institute at Columbia University Lamont Campus, Palisades NY 10964-8000 (845) 680-4450 -- This message (and any attachments) is for the recipient only. NERC is subject to the Freedom of Information Act 2000 and the contents of this email and any reply you make may be disclosed by NERC unless it is exempt from release under the Act. Any material supplied to NERC may be stored in an electronic records management system. ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu
[CF-metadata] CF 1.5 and discrete Sampling Geometries
Hi folks, Can someone please let me know when Discrete Sampling Geometries (https://cf-pcmdi.llnl.gov/trac/wiki/PointObservationConventions) be part of CF officially ? Is this chapter going to be added to CF eventually? Or is this page defunct? I don't see any mention of CF:featureType in the CF-1.5 documentation. Upendra ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
Re: [CF-metadata] potential temperature
Dear Jonathan, I support this proposal, except I'd suggest defining also reference_pressure_for_potential_density. Hopefully, an ocean modeler will weigh in on this, but I think potential density may be directly calculated in ocean models, in which case it would be odd to assume that one should use the reference pressure for temperature in your definition of potential_density. Best regards, Karl On 12/3/10 1:19 PM, Jonathan Gregory wrote: Dear Karl I would suggest that we change the definition of potential temperature so that it says *by default* the reference pressure is 1e5 Pa, but that the data var could also have a size-one coordinate variable or a scalar coordinate variable with the standard_name of reference_pressure_for_potential_temperature, which I am proposing as an addition to the standard_name table, that would specify the reference pressure. This would be backward-compatible because any existing use of sea_water_potential_temperature would be with the default reference pressure by definition. I agree that the definition should have said 1e5 Pa, not sea level pressure, but I am sure that people will have used it as 1e5 Pa and not worried about the difference. If anyone had noticed the definition and been concerned, they would have queried it before. The same issue arises for potential density. Is it OK to use a reference_pressure_for_potential_temperature to define potential density? I think so. It is the temperature which changes; the potential density is computed from the potential temperature. Cheers Jonathan ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
Re: [CF-metadata] Explanation of mass_concentration_of_water_vapor_in_air ?
Sounds like a good idea to me. Philip --- Dr Philip Cameron-Smith, p...@llnl.gov, Lawrence Livermore National Lab. --- -Original Message- From: cf-metadata-boun...@cgd.ucar.edu [mailto:cf-metadata- boun...@cgd.ucar.edu] On Behalf Of Bruno PIGUET Sent: Monday, December 13, 2010 6:53 AM To: cf-metadata Subject: [CF-metadata] Explanation of mass_concentration_of_water_vapor_in_air ? Dear all, Is it possible to make suggestion for the small text describing the names in the CF standard name table ? I yes, I would suggest to modify the text describing mass_concentration_of_water_vapor_in_air. The beginning of the sentence is clear, and anybody is able to understand it (Mass concentration means mass per unit volume). But I think that it may be a valuable addition to write that : the usual name of this quantity in Atmospheric Sciences in absolute humidity. I believe that this would help people searching the standard name table. Bruno. References to this definition, if needed : 1) WORLD METEOROLOGICAL ORGANIZATION, INSTRUMENTS AND OBSERVING METHODS REPORT No. 86 TRAINING MATERIAL ON METROLOGY AND CALIBRATION http://www.wmo.int/pages/prog/www/IMOP/publications/IOM-19-Synoptic- AWS.pdf 2) http://nsidc.org/arcticmet/glossary/absolute_humidity.html -- Bruno PIGUET Mèl : bruno.pig...@meteo.fr | GAME : URA CNRS METEO-FRANCE Tel : +33 (0)5 61 07 96 59 | CNRM/GMEI/TRAMM Fax : +33 (0)5 61 07 96 27 | 42 Av. G. Coriolis Sec : +33 (0)5 61 07 96 63 | 31057 TOULOUSE cedex 1 ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
[CF-metadata] bounds not allowed for scalar coordinate variables
Dear all, Does anyone remember, why we didn't allow the bounds attribute to be attached to a scalar coordinate variable? Currently CF requires the user to include a dimension a size one if he wants to define coordinate bounds: The advantage of using a coordinate variable is that all its attributes can be used to describe the single-valued quantity, including boundaries. Is there any good reason for this restriction on use of a scalar coordinate variable? [Note that we also, don't allow an axis attribute to be attached to a scalar coordinate variable, and I also don't remember why we did this.] Best regards, Karl ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
Re: [CF-metadata] Web reference to a standard name?
A minor clarification as to how MMI is doing things: Benno, all, On Dec 13, 2010, at 07:25, Benno Blumenthal wrote: We have tried to get standard URIs for CF concepts, but the effort bogged down. As for standard names, MMI established a set of URIs at http://marinemetadata.org/cf but has not been keeping up to date. Thanks for the mention. This is our older URL, sorry; we are now maintaining CF standard names in our ontology repository, using resolvable URLs. [1] There was a period when MMI was not keeping up to date with CF changes, but in the recent past we have been continuously updating the SKOS ontology for the parameter names at the site Carlos mentioned [1] (We will forward the misleading /cf URL above, or fix it to make clear in some other way the current status; thanks for calling that out.) As with Roy's handling, we provide URLs both for the current version at the reference URL, and for individual releases of the vocabulary. John [1] http://mmisw.org/ont/cf/parameter I have written a XSL transform at http://iridl.ldeo.columbia.edu/ontologies/xslt/.cfsn2rdf.xsl that can be applied to http://cf-pcmdi.llnl.gov/documents/cf-standard-names/standard-name-table/16/cf-standard-name-table.xml to generate an up-to-date version, e.g. xsltproc http://iridl.ldeo.columbia.edu/ontologies/xslt/.cfsn2rdf.xsl http://cf-pcmdi.llnl.gov/documents/cf-standard-names/standard-name-table/16/cf-standard-name-table.xml On the other hand, Roy has created opaque URIs for standard names at http://vocab.ndg.nerc.ac.uk/list/P07/9 contains all the Standard Names that have ever been published, including names that have been aliased http://vocab.ndg.nerc.ac.uk/list/P071/9 contains the Standard Names that are currently valid (i.e. those that have not been deprecated through aliasing) http://vocab.ndg.nerc.ac.uk/list/P072/9 contains the Standard Names that have been deprecated through aliasing The mapping between deprecates and their replacement aliases my be obtained through the following API call http://vocab.ndg.nerc.ac.uk/axis2/services/vocab/getMap?subjectList=http://vocab.ndg.nerc.ac.uk/list/P072/currentpredicate=255objectList=http://vocab.ndg.nerc.ac.uk/list/P071/currentinference=false he changes them with each version, so it is both more definitive and harder to use. It is also pure SKOS, so one needs to add structure to actually connect it with a CF-described dataset. I plan to write out a map between the two, so that I can use his relationships between CF standard_names, but I do not have it yet. Additional information and ontologies describing the CF structure both as attributes and conceptually are available at http://iridl.ldeo.columbia.edu/ontologies/, including the connections between the standard_name ontologies and the CF structure. Benno On Mon, Dec 13, 2010 at 9:22 AM, Dominic Lowe dominic.l...@stfc.ac.uk wrote: Hello all, What's the current CF recommended scheme for referencing a standard name on the web? (either by URL or URN). I know about the vocab server and the xml/html online versions and could choose to use URLs to point to items in any of these but is there a definitive pattern that should be used? (or at least a best practice that should be encouraged?). Much appreciated, Dominic -- Scanned by iCritical. ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata -- Dr. M. Benno Blumenthal be...@iri.columbia.edu International Research Institute for climate and society The Earth Institute at Columbia University Lamont Campus, Palisades NY 10964-8000 (845) 680-4450 ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata John Graybeal mailto:jgrayb...@ucsd.edu phone: 858-534-2162 System Development Manager Ocean Observatories Initiative Cyberinfrastructure Project: http://ci.oceanobservatories.org Marine Metadata Interoperability Project: http://marinemetadata.org ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
Re: [CF-metadata] Web reference to a standard name?
On Mon, Dec 13, 2010 at 5:27 PM, John Graybeal jbgrayb...@mindspring.comwrote: A minor clarification as to how MMI is doing things: Benno, all, On Dec 13, 2010, at 07:25, Benno Blumenthal wrote: We have tried to get standard URIs for CF concepts, but the effort bogged down. As for standard names, MMI established a set of URIs at http://marinemetadata.org/cf but has not been keeping up to date. Thanks for the mention. This is our older URL, sorry; we are now maintaining CF standard names in our ontology repository, using resolvable URLs. [1] There was a period when MMI was not keeping up to date with CF changes, but in the recent past we have been continuously updating the SKOS ontology for the parameter names at the site Carlos mentioned [1] (We will forward the misleading /cf URL above, or fix it to make clear in some other way the current status; thanks for calling that out.) Glad you have a new system that can need up-to-date. Let me point out two things, very important to me at least. 1) you changed the namespace of the standard names, so your new document is not a direct replacement of the old, you would need to provide a mapping to make the new replace the old. 2) you changed the ontology. SKOS is good and fine, but it makes it impossible to connect to CF -- that is external to what you are providing. Your old ontology, because it was a complete representation of what was in the XML file, gave a handle to map from a XML representation of a netcdf file to the semantic representation of standard names. You cannot get that by a redirect to your SKOS representation. To be more concrete, in my system, I have cfatt:standard_name which is string_valued, and is one of many attributes a variable in a netcdf file can have. If a variable has that string valued attribute, it can be connected to the SKOS term corresponding to the standard name. Since SKOS is deprecating that property, (or at least was last time I looked), I use my own property iriterm:isDescribedBy So my variable has var iriterm:isDescribedBy cfsn:air_temperature. and var cfatt:standard_name air_temperature. when the crosswalking is done. The crosswalk uses the standard_name property of the old Standard_Name objects to connect the objects to the cfatt property of the netcdf variable. SKOS is important for interrelating concepts, but we need to relate to the CF structure as well. Please do not throw away this key piece of the problem in an effort to standardize. Benno As with Roy's handling, we provide URLs both for the current version at the reference URL, and for individual releases of the vocabulary. John [1] http://mmisw.org/ont/cf/parameter I have written a XSL transform at http://iridl.ldeo.columbia.edu/ontologies/xslt/.cfsn2rdf.xsl that can be applied to http://cf-pcmdi.llnl.gov/documents/cf-standard-names/standard-name-table/16/cf-standard-name-table.xml to generate an up-to-date version, e.g. xsltproc http://iridl.ldeo.columbia.edu/ontologies/xslt/.cfsn2rdf.xsl http://cf-pcmdi.llnl.gov/documents/cf-standard-names/standard-name-table/16/cf-standard-name-table.xml On the other hand, Roy has created opaque URIs for standard names at http://vocab.ndg.nerc.ac.uk/list/P07/9 contains all the Standard Names that have ever been published, including names that have been aliased http://vocab.ndg.nerc.ac.uk/list/P071/9 contains the Standard Names that are currently valid (i.e. those that have not been deprecated through aliasing) http://vocab.ndg.nerc.ac.uk/list/P072/9 contains the Standard Names that have been deprecated through aliasing The mapping between deprecates and their replacement aliases my be obtained through the following API call http://vocab.ndg.nerc.ac.uk/axis2/services/vocab/getMap?subjectList=http://vocab.ndg.nerc.ac.uk/list/P072/currentpredicate=255objectList=http://vocab.ndg.nerc.ac.uk/list/P071/currentinference=false he changes them with each version, so it is both more definitive and harder to use. It is also pure SKOS, so one needs to add structure to actually connect it with a CF-described dataset. I plan to write out a map between the two, so that I can use his relationships between CF standard_names, but I do not have it yet. Additional information and ontologies describing the CF structure both as attributes and conceptually are available at http://iridl.ldeo.columbia.edu/ontologies/, including the connections between the standard_name ontologies and the CF structure. Benno On Mon, Dec 13, 2010 at 9:22 AM, Dominic Lowe dominic.l...@stfc.ac.uk wrote: Hello all, What's the current CF recommended scheme for referencing a standard name on the web? (either by URL or URN). I know about the vocab server and the xml/html online versions and could choose to use URLs to point to items in any of these but is there a definitive pattern that should be used? (or at least a best practice that should be
Re: [CF-metadata] bounds not allowed for scalar coordinate variables
On 12/13/2010 1:50 PM, Karl Taylor wrote: Dear all, Does anyone remember, why we didn't allow the bounds attribute to be attached to a scalar coordinate variable? Currently CF requires the user to include a dimension a size one if he wants to define coordinate bounds: The advantage of using a coordinate variable is that all its attributes can be used to describe the single-valued quantity, including boundaries. Is there any good reason for this restriction on use of a scalar coordinate variable? Hi Karl, I cannot at the moment think of any outright contradictions that arise from allowing scalar variables to have the status of full-fledged (degenerate) coordinate variables, as long as they are pointed to by some dependent variable using a coordinates attribute. Having said that, I think we should always weigh new proposals against Michi Henning's advice about creating standards: 'the ability to say no is usually far more important than the ability to say yes.' By offering two encodings for the same information we have added no power to CF, but we have made the task of writing interpreters harder. We have opened the door wider to unanticipated contradictions; we have closed a door on alternative interpretations of a syntax that we might be wishing for in the future. [Note that we also, don't allow an axis attribute to be attached to a scalar coordinate variable, and I also don't remember why we did this.] There are valid reasons to argue that coordinate variables should be self-identifying -- i.e. that their interpretation does not rely on the presence of some other variable bearing a coordinates attribute that points to them. This requirement would allow the coordinates in a file to be identified in a single pass; it would ensure that the interpretation of the file is not subtly corrupted by the removal of a dependent variable. Traditional netCDF coordinate variables (dimension name = variable name) pass this test. All forms of auxiliary coordinate variable (including scalar coordinates) pass this test _only if_ they possess an axis attribute. (The units= attribute is not a reliable indicator of an independent coordinate.) So from my pov scalar variables should be _required_ to include an axis attribute. Ditto for other auxiliary coordinate variables.(Jonathan Gregory and I recently concluded that there are ambiguities in the interpretation of the axis attribute as currently documented.) - Steve === Best regards, Karl ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
Re: [CF-metadata] potential temperature
I am a bit rusty at this, but in the ocean potential temperature and salinity are preserved in an adiabatic transition, potential density is not because the eq-of-state is non-linear. So potential density is spoken of in the ocean, but it gets one into trouble because if parcels are moved far enough to the reference pressure, the relative potential_density of the two can switch. So I would think potential_temperature is the better choice of variable for a modeler, and reference_pressure_for_potential_temperature is in fact an accurate description of the situation even for potential_density (salinity does not have a reference pressure). Benno On Mon, Dec 13, 2010 at 3:11 PM, Karl Taylor taylo...@llnl.gov wrote: Dear Jonathan, I support this proposal, except I'd suggest defining also reference_pressure_for_potential_density. Hopefully, an ocean modeler will weigh in on this, but I think potential density may be directly calculated in ocean models, in which case it would be odd to assume that one should use the reference pressure for temperature in your definition of potential_density. Best regards, Karl On 12/3/10 1:19 PM, Jonathan Gregory wrote: Dear Karl I would suggest that we change the definition of potential temperature so that it says *by default* the reference pressure is 1e5 Pa, but that the data var could also have a size-one coordinate variable or a scalar coordinate variable with the standard_name of reference_pressure_for_potential_temperature, which I am proposing as an addition to the standard_name table, that would specify the reference pressure. This would be backward-compatible because any existing use of sea_water_potential_temperature would be with the default reference pressure by definition. I agree that the definition should have said 1e5 Pa, not sea level pressure, but I am sure that people will have used it as 1e5 Pa and not worried about the difference. If anyone had noticed the definition and been concerned, they would have queried it before. The same issue arises for potential density. Is it OK to use a reference_pressure_for_potential_temperature to define potential density? I think so. It is the temperature which changes; the potential density is computed from the potential temperature. Cheers Jonathan ___ CF-metadata mailing listcf-metad...@cgd.ucar.eduhttp://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata -- Dr. M. Benno Blumenthal be...@iri.columbia.edu International Research Institute for climate and society The Earth Institute at Columbia University Lamont Campus, Palisades NY 10964-8000 (845) 680-4450 ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
