[Esip-documentation] cdm_data_type defintion

[Armstrong, Edward M (398G)]

Yes it does seem to be a problem child ;)

Thanks for your response.

On Feb 19, 2015, at 10:33 AM, Bob Simons - NOAA Federal <bob.simons at noaa.gov<mailto:bob.simons at noaa.gov>> wrote:

I think cdm_data_type is a troubled attribute.
Unidata has released several different lists of CDM data types over the years as CDM progressed. Those all still exist at various URLs on the web and in Unidata code (some of it obsolete).
CF has a new(er), closely related featureType attribute
http://cfconventions.org/Data/cf-conventions/cf-conventions-1.6/build/cf-conventions.html#idp6280704
but it is unfortunately just for Discrete Sampling Geometry types.

I think ACDD 1.3 chose to avoid dealing with this in hopes that CF will solve the problem. E.g., CF might/should expand the use of featureType.

I think ERDDAP may be the only software which actually uses this attribute in a very specific, programmatic way, which is vocabulary which is a combo of
* the values that CF's featureType uses (from just before CF created the featureType attribute), e.g., TimeSeries.
* a few other Unidata CDM types, e.g., Grid
* "Other"
http://coastwatch.pfeg.noaa.gov/erddap/download/setupDatasetsXml.html#cdm_data_type

I'm sorry there isn't a better answer.


On Thu, Feb 19, 2015 at 9:51 AM, Armstrong, Edward M (398G) via Esip-documentation <esip-documentation at lists.esipfed.org<mailto:esip-documentation at lists.esipfed.org>> wrote:

Hi folks

I’ve come across a request for the proper usage of the ACDD attribute cdm_data_type.  This has been retained in  ver 1.3.   But what are the examples of its implementation ? According to:

http://www.unidata.ucar.edu/software/thredds/current/tds/catalog/InvCatalogSpec.html#dataType

attribute examples could “Grid” ,“Swath”, “Point" etc.  But some popular implementation embedded in existing examples use a lowercase syntax such as “swath”

Which is the proper implementation, upper vs lowercase ?  Or perhaps this is still nebulous.  I did find this note from Bob Simmons in our recent ACCD v1.3 discussion on a google doc spreadsheet (but I don’t remember the consensus  on it):

cdm_data_type should not be tied to
http://www.unidata.ucar.edu/software/thredds/current/tds/catalog/InvCatalogSpec.html#dataType
which is out-of-date and obsolete

Any insight appreciated.

-ed

Ed Armstrong
JPL Physical Oceanography DAAC
818 519-7607<tel:818%20519-7607>




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--
Sincerely,

Bob Simons
IT Specialist
Environmental Research Division
NOAA Southwest Fisheries Science Center
99 Pacific St., Suite 255A      (New!)
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Fax:   (831)648-8440
Email: bob.simons at noaa.gov<mailto:bob.simons at noaa.gov>

The contents of this message are mine personally and
do not necessarily reflect any position of the
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<>< <>< <>< <>< <>< <>< <>< <>< <><


-ed

Ed Armstrong
JPL Physical Oceanography DAAC
818 519-7607



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