[ncl-talk] CNL read CALIPSO v4.51 data

[Rick Brownrigg]

h5dump can't open it.  Running "strings" on that filename indicates its an
HDF4.2 file?



On Thu, Sep 4, 2025 at 3:30 PM Dave Allured - NOAA Affiliate via ncl-talk <
ncl-talk at mailman.ucar.edu> wrote:

> More diagnostics needed.  Someone please show output from:
>
> NCL:
> fh = addfile("CAL_LID_L2_VFM-Standard-V4-51.2017-08-21T14-
> 00-11ZD.hdf","r")
> print (fh)
>
> Linux:
> h5dump -BH CAL_LID_L2_VFM-Standard-V4-51.2017-08-21T14-00-11ZD.hdf
>
>
> On Thu, Sep 4, 2025 at 3:23 PM Rick Brownrigg via ncl-talk <
> ncl-talk at mailman.ucar.edu> wrote:
>
>> Hi,
>>
>> As that file resides on /glade, I was able to access it and duplicate the
>> problem. I can print() that variable, but I can't load it into an NCL
>> variable. Its rather large -- 699MB. Perhaps that's the problem?
>> Interestingly, if I run "ncdump" on that file, I get:
>>
>>  ncdump
>> /glade/derecho/scratch/zhifengy/data/experiment_input/doe_cloud_africa/CALIPSO/CAL_LID_L2_VFM-Standard-V4-51/test/CAL_LID_L2_VFM-Standard-V4-51.2017-08-21T14-00-11ZD.hdf
>>
>> ncdump:
>> /glade/derecho/scratch/zhifengy/data/experiment_input/doe_cloud_africa/CALIPSO/CAL_LID_L2_VFM-Standard-V4-51/test/CAL_LID_L2_VFM-Standard-V4-51.2017-08-21T14-00-11ZD.hdf:
>> NetCDF: Attempt to use feature that was not turned on when netCDF was built.
>>
>> Rick
>>
>>
>> On Thu, Sep 4, 2025 at 3:16 PM Ehsan Taghizadeh via ncl-talk <
>> ncl-talk at mailman.ucar.edu> wrote:
>>
>>> Hi Zhifeng,
>>>
>>> Could you please add the following commands before your addfile command:
>>>
>>> exists =
>>> isfilepresent("CAL_LID_L2_VFM-Standard-V4-51.2017-08-21T14-00-11ZD.hdf")
>>> print (exists)
>>>
>>> I wonder if your ncl script and the file are in the same place.
>>> In case it returns True, could you please add the following commands
>>> just after reading your file (after addfile command):
>>>
>>> names = getfilevarnames(
>>> "CAL_LID_L2_VFM-Standard-V4-51.2017-08-21T14-00-11ZD.hdf")
>>> print (names)
>>>
>>>
>>> *-----------------------------------------------------------------------------*
>>> *Best regards,*
>>> *Ehsan Taghizadeh*
>>>
>>>
>>> On Thursday, September 4, 2025 at 01:37:05 PM PDT, Zhifeng Yang via
>>> ncl-talk <ncl-talk at mailman.ucar.edu> wrote:
>>>
>>>
>>> Hi all,
>>>
>>> I am using NCL 6.6.2 to read CALIPSO latitude, longitude, and
>>> Feature_Classification_Flags variable from CAL_LID_L2_VFM-Standard-V4-51.
>>>
>>>   fh =
>>> addfile("CAL_LID_L2_VFM-Standard-V4-51.2017-08-21T14-00-11ZD.hdf","r")
>>>    lath      = fh->Latitude(:, 0)
>>>    lonh      = fh->Longitude(:, 0)
>>>    vfmh      = fh->Feature_Classification_Flags
>>>
>>> However, I got the error below
>>> fatal:HDF: An error occurred while attempting to read variable
>>> (Feature_Classification_Flags) from file
>>> (/glade/derecho/scratch/zhifengy/data/experiment_input/doe_cloud_africa/CALIPSO/CAL_LID_L2_VFM-Standard-V4-51/test/CAL_LID_L2_VFM-Standard-V4-51.2017-08-21T14-00-11ZD.hdf)
>>>
>>> Do you have any idea about this? Thanks,
>>>
>>> Best,
>>> Zhifeng
>>>
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