[ncl-talk] Editing a netcdf4 file

[David Brown]

Dustan and Gerry,
This issue relating to writing a variable with chunking in an existing
NetCDF4 file has been fixed. Also a secondary issue involving
re-writing existing variable attributes has been addressed as well.
Let us know if you need a version with these fixes and we will try to
accommodate you as soon as possible.
Thanks for letting us know of this problem.
 -dave


On Wed, Jun 3, 2015 at 8:50 AM, David Brown <dbrown at ucar.edu> wrote:
> Hi Dustin and Gerry,
> I have confirmed there is a problem. It has been partially but not
> completely fixed in the development version of the code. I am looking
> into the remaining issue and will let you know when it has been fixed.
>  -dave
>
> On Tue, Jun 2, 2015 at 10:34 AM, Gerry Creager - NOAA Affiliate
> <gerry.creager at noaa.gov> wrote:
>> Additional information: If we do an addfile("<filename>","r"), we can open
>> and read the file. If we use "w", well, we can open the file but assigning
>> an existing variable to an internal variable fails on the assign (var =
>> a->QRAIN). Of course, because it fails there, we can't see if it'd also fail
>> on write.
>>
>> Thanks
>> Gerry
>>
>> On Mon, Jun 1, 2015 at 7:15 PM, Gerry Creager - NOAA Affiliate
>> <gerry.creager at noaa.gov> wrote:
>>>
>>> I've started looking at this with Dusty. Appreciate any thought you might
>>> have as to why we're failing.
>>>
>>> I've uploaded the input file (wrfinput_d02) to the FTP incoming site. I'm
>>> testing with the script:
>>>
>>> var = "QRAIN"
>>> print(var)
>>> a=addfile("wrfinput_d02.nc", "w")
>>> var_orig=a->QRAIN
>>> print(var_orig)
>>>
>>>
>>> The result looks like:gerry at loki:~/NEWSe/NCL> ncl test.ncl
>>>  Copyright (C) 1995-2015 - All Rights Reserved
>>>  University Corporation for Atmospheric Research
>>>  NCAR Command Language Version 6.3.0
>>>  The use of this software is governed by a License Agreement.
>>>  See http://www.ncl.ucar.edu/ for more details.
>>>
>>>
>>> Variable: var
>>> Type: string
>>> Total Size: 8 bytes
>>>             1 values
>>> Number of Dimensions: 1
>>> Dimensions and sizes: [1]
>>> Coordinates:
>>> (0) QRAIN
>>> fatal:["NclNetCDF4.c":3073]:NclNetCDF4.c: Error in nc_def_var_chunking in
>>> file (wrfinput_d02.nc) for writing, at line: 3073
>>>
>>> line 3074 of NclNetCDF4.c: NetCDF: Attempt to define var properties, like
>>> deflate, after enddef.
>>>
>>>
>>> On Fri, May 29, 2015 at 8:54 PM, Dustan Wheatley - NOAA Affiliate
>>> <dustan.wheatley at noaa.gov> wrote:
>>>>
>>>> I am trying to overwrite a netcdf4 file analogous to what is shown at
>>>> http://www.ncl.ucar.edu/Applications/change_netCDF.shtml.  In the attached
>>>> ncl script, I open the file to be modified at line 35 and attempt the
>>>> modification at line 73 (with a lot of calculations in between).  While I
>>>> have double-checked that the modified field (var_mod) has the same
>>>> dimensionality as the original variable (QRAIN), I am still get a
>>>> segmentation fault/core dump.  Never had this problem when I tried to
>>>> manipulate netcdf3 files.  Could it possibly be related to the netcdf4
>>>> compression?  It’s possible I may be trying to do something that’s no longer
>>>> possible.
>>>>
>>>> Thanks in advance for any suggestions.
>>>>
>>>> -Dusty Wheatley
>>>>
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>>>
>>>
>>>
>>> --
>>> Gerry Creager
>>> NSSL/CIMMS
>>> 405.325.6371
>>> ++++++++++++++++++++++
>>> “Big whorls have little whorls,
>>> That feed on their velocity;
>>> And little whorls have lesser whorls,
>>> And so on to viscosity.”
>>> Lewis Fry Richardson (1881-1953)
>>
>>
>>
>>
>> --
>> Gerry Creager
>> NSSL/CIMMS
>> 405.325.6371
>> ++++++++++++++++++++++
>> “Big whorls have little whorls,
>> That feed on their velocity;
>> And little whorls have lesser whorls,
>> And so on to viscosity.”
>> Lewis Fry Richardson (1881-1953)
>>
>> _______________________________________________
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