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Gang,
I think the <promoteGlobalAttribute> would work if you had a global
attribute of type {int,float,double} that indicated some number of
time units (hours, days, seconds) from a common origin.
Then those attributes would be promoted to a variable on aggregation,
and you could then define the units.
But if your global attribute is defined time as a string, then
promoteGlobalAttribute wouldn't help you get a numeric CF-compliant
time array.
-Rich
On Tue, Mar 19, 2013 at 4:09 PM, Roy Mendelssohn - NOAA Federal
<roy.mendelssohn@xxxxxxxx> wrote:
> I should add that this arises only because the dateFormatMark when used in
> aggregation creates a string for time, rather than a number, and therefore
> breaks tools looking for CF compliance. This issue has been brought up
> several times before.
>
> Even more curious, under TDS 4.3.15, if i have a GRIB featureCollection and
> use dateFormatMark on the file name to aggregate times, the times are
> numbers in the usual "units-since-some-basetime"
>
> So, can we either get GRIDS under featureCollections with the dateFormatMark
> behaving in a similar manner, or at least have the option in the normal scan
> aggregation to tell dateFormatMark to return the time as a number? Without
> naming names, I know there are others who would benefit from this.
>
> Thanks,
>
> -Roy
> On Mar 19, 2013, at 12:36 PM, Bob Simons - NOAA Federal <bob.simons@xxxxxxxx>
> wrote:
>
>> Is there a way to promote a global numeric attribute to be a new coordinate
>> variable?
>> I read the bottom of
>> http://www.unidata.ucar.edu/software/netcdf/ncml/v2.2/Cookbook.html
>> but I am confused (time vs times? and why dateFormatMark which also seems to
>> be creating an ISO 8601 time axis?).
>> Can someone provide a more complete, less confusing, working example?
>>
>> My best guess at the ncml is:
>>
>> <netcdf xmlns="http://www.unidata.ucar.edu/namespaces/netcdf/ncml-2.2";>
>> <variable name="time" type="int" shape="time" >
>> <attribute name="units" value="days since 2012-12-31"/>
>> <attribute name="_CoordinateAxisType" value="Time" />
>> </variable>
>> <aggregation dimName="time" type="joinNew" recheckEvery="15 min" >
>> <variableAgg name="chla"/>
>> <promoteGlobalAttribute name="time" orgName="startDay" />
>> <scan location="/testFiles/" suffix=".hdf" subdirs="false" />
>> </aggregation>
>> ...
>>
>> I have tried lots of variations, to no avail.
>> I have tried lots of variations with joinExisting, with and without the
>> <variable>, to no avail.
>> They almost all generate an unhelpful error message like:
>>
>> Exception in thread "main" java.lang.NullPointerException
>> at
>> ucar.nc2.ncml.AggregationOuterDimension.promoteGlobalAttributes(AggregationOuterDimension.java:176)
>> at
>> ucar.nc2.ncml.AggregationNew.buildNetcdfDataset(AggregationNew.java:73)
>> at ucar.nc2.ncml.Aggregation.finish(Aggregation.java:404)
>> at ucar.nc2.ncml.NcMLReader.readNetcdf(NcMLReader.java:492)
>> at ucar.nc2.ncml.NcMLReader.readNcML(NcMLReader.java:437)
>> at ucar.nc2.ncml.NcMLReader.access$100(NcMLReader.java:60)
>> at
>> ucar.nc2.ncml.NcMLReader$NcmlElementReader.open(NcMLReader.java:1406)
>> at
>> ucar.nc2.ncml.NcMLReader$NcmlElementReader.open(NcMLReader.java:1394)
>> at ucar.nc2.dataset.NetcdfDataset.acquireFile(NetcdfDataset.java:625)
>> at ucar.nc2.ncml.Aggregation$Dataset.acquireFile(Aggregation.java:634)
>> at
>> ucar.nc2.ncml.AggregationUnion.buildNetcdfDataset(AggregationUnion.java:65)
>> at ucar.nc2.ncml.Aggregation.finish(Aggregation.java:404)
>> at ucar.nc2.ncml.NcMLReader.readNetcdf(NcMLReader.java:492)
>> at ucar.nc2.ncml.NcMLReader.readNcML(NcMLReader.java:437)
>> at ucar.nc2.ncml.NcMLReader.readNcML(NcMLReader.java:252)
>> at ucar.nc2.ncml.NcMLReader.readNcML(NcMLReader.java:202)
>> at ucar.nc2.dataset.NetcdfDataset.acquireNcml(NetcdfDataset.java:847)
>> at
>> ucar.nc2.dataset.NetcdfDataset.openOrAcquireFile(NetcdfDataset.java:686)
>> at ucar.nc2.dataset.NetcdfDataset.openFile(NetcdfDataset.java:563)
>> at ucar.nc2.NCdumpW.print(NCdumpW.java:212)
>>
>>
>> Any suggestions?
>>
>> Thank you.
>>
>> Sincerely,
>>
>> Bob Simons
>> IT Specialist
>> Environmental Research Division
>> NOAA Southwest Fisheries Science Center
>> 1352 Lighthouse Ave
>> Pacific Grove, CA 93950-2079
>> Phone: (831)658-3205
>> Fax: (831)648-8440
>> Email: bob.simons@xxxxxxxx
>>
>> The contents of this message are mine personally and
>> do not necessarily reflect any position of the
>> Government or the National Oceanic and Atmospheric
>> Administration.
>> <>< <>< <>< <>< <>< <>< <>< <>< <><
>>
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>
> **********************
> "The contents of this message do not reflect any position of the U.S.
> Government or NOAA."
> **********************
> Roy Mendelssohn
> Supervisory Operations Research Analyst
> NOAA/NMFS
> Environmental Research Division
> Southwest Fisheries Science Center
> 1352 Lighthouse Avenue
> Pacific Grove, CA 93950-2097
>
> e-mail: Roy.Mendelssohn@xxxxxxxx (Note new e-mail address)
> voice: (831)-648-9029
> fax: (831)-648-8440
> www: http://www.pfeg.noaa.gov/
>
> "Old age and treachery will overcome youth and skill."
> "From those who have been given much, much will be expected"
> "the arc of the moral universe is long, but it bends toward justice" -MLK Jr.
>
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