Re: [thredds] remove dimension with ncml?

• To: John Caron <caron@xxxxxxxxxxxxxxxx>
• Subject: Re: [thredds] remove dimension with ncml?
• From: Dan Swank <Dan.Swank@xxxxxxxx>
• Date: Wed, 23 Mar 2011 16:34:43 -0400

John,
I must reopen this topic.

I am attempting to make a grads friendly catalog for the
GFS 004 on NCDC-NOMADS so that it can be used
in grads via opendap service.  The trouble is
the z dimensions.  There are about a dozen GRIB
"z level types" and grads (which can only deal with
a single z/vertical dim.) - it appears to be selecting the first
z-type dimension it appears on the openDap form ~
Which is not the one I want it to use.

So inside my <netcdf> element.  I tried:

        <remove name="altitude_above_msl" type="dimension" />
            <remove name="ugrdHgtMsl" type="variable" />
            <remove name="vgrdHgtMsl" type="variable" />
            <remove name="tmpHgtMsl" type="variable" />


Simply removing the dimension (the first line) invalidates
the 3 parameters below it which require it.  So I needed to remove
those also.  After removing the variables the opendap form will
work, but the altitude_above_msl z-dim does NOT go away and
grads is still attempting to use it.

Is there actually a way to permanently remove a redundant dimension
  from existence?   (How exactly?)
I can include the remainder of the code block if needed.

        -Dan



John Caron wrote the following on 2/22/2011 8:50 AM:
> On 10/21/2010 8:36 AM, Remon Sadikni wrote:
>>  Dear THREDDS Users,
>>
>> I do not manage to remove a dimension with NcML. I want to remove the
>> dimension called ensemble from a variable thetao, which has 5
>> dimensions: time, ensemble, level, lat, lon, because Ferret (and LAS)
>> can only read in 4 dimensional variables. Maybe you can see a mistake
>> in my code?
>>
>> <dataset name="test" ID="test" urlPath="test">
>> <metadata inherited="true">
>> <serviceName>odap</serviceName>
>> <dataType>Grid</dataType>
>> </metadata>
>> <netcdf xmlns="http://www.unidata.ucar.edu/namespaces/netcdf/ncml-2.2";
>> location="http://...";>
>> <remove name="ensemble" type="dimension" />
>> </netcdf>
>> </dataset>
>>
>> Or is it not possible to remove a dimension? I found this possibility
>> in the NcML-2.2 Schema, but I did not find any examples for removing
>> dimensions. I should also mention, that I access the File via OPeNDAP
>> in the location attribute of the netcdf-tag, but this should be no
>> problem, because I managed to remove variables in the same way
>> (<remove name="level" type="variable">).
>>
>> Thank you very much!
>> Regards,
>> Remon
>>
>> _______________________________________________
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>> thredds@xxxxxxxxxxxxxxxx
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>> http://www.unidata.ucar.edu/mailing_lists/ 
> Hi Remon:
> 
> You can remove a dimension object, but it sounds like you want to
> reshape a variable, which is quite different. Is that correct?
> 
> John
> 
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-- 
Dan Swank
STG, Incorporated - Government Contractor
NCDC-NOMADS Project:  Software & Data Management
Data Access Branch
National Climatic Data Center
Veach-Baley Federal Building
151 Patton Avenue
Asheville, NC 28801-5001
Email: Dan.Swank@xxxxxxxx
Phone: 828-271-4007

• References:
  • Re: [thredds] remove dimension with ncml?
    • From: John Caron