Re: Question about CDM

• To: Pauline Mak <pauline@xxxxxxxxxxxx>
• Subject: Re: Question about CDM
• From: John Caron <caron@xxxxxxxxxxxxxxxx>
• Date: Tue, 24 Apr 2007 09:44:56 -0600

Pauline Mak wrote:

Hi all,

Thanks for the help - through the second validator, I think I've found out what's wrong with the dataset. Some of the axis doesn't have any values under the regular column. I've written a little Java app that goes through a directory and find all nc files and checks that a) it opens up as a GriddedDataset and then 2) the GridCoordSystem from the GriddedDataset isRegularSpatial(). Is this what it means by the WCS standard that it has to be gridded and regularly spaced?

Thanks,

-Pauline.

On 4/21/07, *Ethan Davis* <edavis@xxxxxxxxxxxxxxxx <mailto:edavis@xxxxxxxxxxxxxxxx>> wrote:

    Hi Pauline,

    Another resource for validating datasets against the CDM is available at

    http://motherlode.ucar.edu:8080/thredds/cdmValidate.html
    <http://motherlode.ucar.edu:8080/thredds/cdmValidate.html>

    And I believe it is distributed with all TDS installations, so you could
    try it locally at http://yourserver:port/thredds/cdmValidate.html

    Which datasets can be served by the TDS depends on the service over
    which you want to make them available. The HTTP bulk file download
    service (/thredds/fileServer/) can serve any file. The OPeNDAP service
    (/thredds/dodsC/) can serve any dataset that the netCDF-java library
    can
    read (the file types that can be read are listed on the home page,
    http://www.unidata.ucar.edu/software/netcdf-java/). The WCS service
    currently only handles gridded data. The key here is that they have to
    be recognized as gridded datasets by the netCDF-java library. The
    library can recognize gridded data and the coordinates in the data using
    a few different conventions. As Tom and/or Roy mentioned, CF is the
    convention we recommend. The CDM validator above should give you more
    clues on how well you dataset validates.

    Hope that helps.

    Ethan

    Pauline Mak wrote:
     > Hi all,
     >
     > I'm currently setting up a THREDDS server to server our
    datasets.  The
     > setup was fairly easy!  However, I'm running into problems with
    NetCDF
     > files which doesn't conform to the "Common Data (Access) Model" - we
     > want to serve all of our data through WCS (which comes for free with
     > THREDDS data server!).  I've searched high and low for documentation
     > on how to 'correct'  incompatible files. but failed to come up with
     > anything.  Am I missing something? Should all NetCDF files "just
    work"
     > with the NetCDF-Java 2.2 library?  I'm aware that files should be
     > gridded and regular.  Am I understanding correctly that gridded means
     > the files should have an x and y axis with optional z and t?   Is
     > there a nice method to find out if a file is compatible and if it's
     > not compatible, why it is so?
     >
     > My understanding of NetCDF file is rather shallow... so please bear
     > with me if I'm asking a simple question...
     >
     > Thanks & cheers,
     >
     > -Pauline.
     >
     > --
     > Pauline Mak
     > Software Developer, Insight4
     > Suite 2 / Level 1, 114 Murray St.
     > Hobart, Australia 7000
     > p:  (03) 6234 5203
     > f:  (03) 6234 5603
     > pauline@xxxxxxxxxxxx <mailto:pauline@xxxxxxxxxxxx>
    <mailto:pauline@xxxxxxxxxxxx <mailto:pauline@xxxxxxxxxxxx>>

    --
    Ethan R. Davis                                Telephone: (303) 497-8155
    Software Engineer                             Fax:       (303) 497-8690

UCAR Unidata Program Center E-mail: edavis@xxxxxxxx <mailto:edavis@xxxxxxxx>

    P.O. Box 3000

Boulder, CO 80307-3000 http://www.unidata.ucar.edu/

    ---------------------------------------------------------------------------





--
--
Pauline Mak
Software Developer, Insight4
Suite 2 / Level 1, 114 Murray St.
Hobart, Australia 7000
p:  (03) 6234 5203
f:  (03) 6234 5603
pauline@xxxxxxxxxxxx <mailto:pauline@xxxxxxxxxxxx>

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• Follow-Ups:
  • RE: Question about CDM
    • From: Woolf, A (Andrew)

• References:
  • Question about CDM
    • From: Pauline Mak
  • Re: Question about CDM
    • From: Ethan Davis
  • Re: Question about CDM
    • From: Pauline Mak