Yes in my opinion, this is worth issues in both the netcdf-c and
netcdf-python libraries, but at low priority. I think this is a relatively
obscure case. The hope is that if fixed in the libraries, it will avoid
more debugging efforts by future users.
On Wed, Oct 2, 2024 at 3:10 PM Chris Barker <chris.barker@xxxxxxxx> wrote:
> On Wed, Oct 2, 2024 at 1:44 PM Dave Allured - NOAA Affiliate via
> netcdfgroup <netcdfgroup@xxxxxxxxxxxxxxxx> wrote:
>
>> This file was probably written by a pre-2013 version of the netcdf-C
>> library,
>>
>
> Ahh, that may explain it.
>
>
>> Modern libraries choke on the type mismatch, as seen here.
>>
> ...
>
>> However IMO, libraries should also support problem-free writes to such
>> existing files.
>>
>
> Is this worth an issue on the netCDF C lib?
>
> -CHB
>
>
>
>> It may be possible to "fix" files like this, by replacing or deleting the
>> offending _FillValue attributes with lower level or capable software, such
>> as the HDF5 library.
>>
>>
>> On Wed, Oct 2, 2024 at 1:58 PM Chris Barker via netcdfgroup <
>> netcdfgroup@xxxxxxxxxxxxxxxx> wrote:
>>
>>> I was wondering what the NaNf meant :-)
>>>
>>> But yeah, that's probably it -- now to track down whoever wrote this
>>> file --
>>> But I do wonder what software allowed this?
>>>
>>> -CHB
>>>
>>>
>>> On Wed, Oct 2, 2024 at 12:53 PM Benjamin Root <ben.v.root@xxxxxxxxx>
>>> wrote:
>>>
>>>> I think the issue is that the _FillValue of "NaN" is probably a float64
>>>> while the variable's dtype is float32, which is probably what it means by a
>>>> type mismatch. When I have a NaN FillValue for a float32 variable, it
>>>> prints "NaNf"
>>>>
>>>> ```
>>>> float sum_tp_mm(time, latitude, longitude) ;
>>>> sum_tp_mm:_FillValue = NaNf ;
>>>> ```
>>>>
>>>
>>
>> On Wed, Oct 2, 2024 at 12:05 PM Chris Barker via netcdfgroup <
>> netcdfgroup@xxxxxxxxxxxxxxxx> wrote:
>>
>>> Thanks Roy, at least it's not just us, and that error did give me a
>>> hint, look at this from ncdump-ing the header:
>>>
>>> float uo(time, depth, latitude, longitude) ;
>>> string uo:units = "m s-1" ;
>>> uo:_FillValue = NaN ;
>>> string uo:standard_name = "eastward_sea_water_velocity" ;
>>> string uo:long_name = "Eastward velocity" ;
>>>
>>> There's no type for the uo:_FillValue attribute.
>>>
>>> How in the world did that happen?
>>>
>>> At least now I have a specific thing to point the file creators to.
>>>
>>> -CHB
>>>
>>>
>>> On Wed, Oct 2, 2024 at 10:58 AM Roy Mendelssohn - NOAA Federal <
>>> roy.mendelssohn@xxxxxxxx> wrote:
>>>
>>>> I can reproduce the error. I tried to copy the file using mccoy, got
>>>> the following:
>>>>
>>>> nccopy cmems_mod_nws_phy_anfc_0.027deg-3D_P1D-m_1727700325546.nc
>>>> test.nc
>>>> NetCDF: Not a valid data type or _FillValue type mismatch
>>>> Location: file ?; fcn ? line 1408
>>>>
>>>> hope this helps.
>>>>
>>>> -Roy
>>>>
>>>>
>>>> > On Oct 2, 2024, at 10:46 AM, Chris Barker via netcdfgroup <
>>>> netcdfgroup@xxxxxxxxxxxxxxxx> wrote:
>>>> >
>>>> > I have a user unable to use a netcdf file with our code.
>>>> >
>>>> > It turns out that the file works just fine when read, but if you try
>>>> to open it for writing, it chokes:
>>>> >
>>>> > (this is the netCDF4 Python lib, version 1.6.5, which seems to be the
>>>> latest release)
>>>> >
>>>> > I get:
>>>> > In [3]: netCDF4.Dataset('
>>>> cmems_mod_nws_phy_anfc_0.027deg-3D_P1D-m_1727700325546.nc', 'r+')
>>>> >
>>>> ---------------------------------------------------------------------------
>>>> > OSError Traceback (most recent call
>>>> last)
>>>> > Cell In[3], line 1
>>>> > ----> 1 netCDF4.Dataset('
>>>> cmems_mod_nws_phy_anfc_0.027deg-3D_P1D-m_1727700325546.nc', 'r+')
>>>> >
>>>> > File src/netCDF4/_netCDF4.pyx:2469, in
>>>> netCDF4._netCDF4.Dataset.__init__()
>>>> >
>>>> > File src/netCDF4/_netCDF4.pyx:2028, in
>>>> netCDF4._netCDF4._ensure_nc_success()
>>>> >
>>>> > OSError: [Errno -103] NetCDF: Can't write file: '
>>>> cmems_mod_nws_phy_anfc_0.027deg-3D_P1D-m_1727700325546.nc'
>>>> >
>>>> > Any idea how I can get more info as to what's wrong with it?
>>>> >
>>>> > Again, we have had no problems reading the file.
>>>> >
>>>> > Thanks,
>>>> > - CHB
>>>> >
>>>> > File is 1.2MB, (not huge by today's standards?) so I've attached it
>>>> here if anyone wants to take a look.
>>>> > --
>>>> > Christopher Barker, Ph.D.
>>>> > Oceanographer
>>>> >
>>>> > Emergency Response Division
>>>> > NOAA/NOS/OR&R (206) 526-6959 voice
>>>> > 7600 Sand Point Way NE (206) 526-6329 fax
>>>> > Seattle, WA 98115 (206) 526-6317 main reception
>>>> >
>>>> > Chris.Barker@xxxxxxxx
>>>
>>>
