[ncl-talk] [ncarg-talk] [6.4.0 version] Bug : Categorical Snow always null

[Mary Haley]

Sébastien,

We downloaded some similar files from:

https://nomads.ncdc.noaa.gov/data/meso-eta-hi/

and didn't see any issues with them, using both older and current versions
of NCL.

Can you tell us what the source of this file is? I'm wondering if it's
possibly a "non-standard" GRIB file (I realize there are no GRIB standards
really, but some files do violate particular rules).

--Mary


On Thu, Jan 11, 2018 at 9:51 AM, Mary Haley <haley at ucar.edu> wrote:

> Hi Sébastien,
>
> Sorry I didn't respond sooner.  I was at a conference.
>
> Thanks for providing a small file that clearly shows the problem.
>
> I have submitted a ticket on this, NCL-2712, and put a high priority on it.
>
> You are correct that it appears to be setting all the 1s to 0s. This is
> very puzzling. I will see if we can look at this soon.
>
> --Mary
>
>
>
> On Tue, Jan 9, 2018 at 4:24 AM, Sébastien POITEVIN <sebastien.poitevin@
> meteoconsult.com> wrote:
>
>> Dear Mary,
>>
>> Thanks for your help.
>>
>>  Find in attached, WRF-NMM grib file and, below, asked informations :
>>
>>
>>
>>    1. No error return with ncl_filedump
>>    2.
>>
>>
>> *printVarSummary(csnow) : Variable: csnowType: floatTotal Size: 1443112
>>    bytes            360778 valuesNumber of Dimensions: 2Dimensions and sizes:
>>     [g0_lat_0 | 529] x [g0_lon_1 | 682]Coordinates:            g0_lat_0:
>>    [53.012..39.787]            g0_lon_1: [-6.01..11.722]Number Of Attributes:
>>    12  center :      US National Weather Service - NCEP (WMC)  long_name :
>>     Categorical snow  units :       yes=1;no=0  _FillValue :  1e+20
>>    level_indicator :     1  gds_grid_type :       0  parameter_table_version
>>    :     2  parameter_number :    143  model :       North Pacific Hurricane
>>    Wave Model  forecast_time :       18  forecast_time_units : hours
>>    initial_time :        01/08/2018 (18:00) *
>>    3.
>> *printMinMax(csnow,0) *
>>    (0)     Categorical snow: min=0   max=0
>>
>>    4.
>>
>>
>> *print(num(ismissing(csnow))) (0)     61086 *
>>
>>
>> 2018-01-08 17:16 GMT+01:00 Mary Haley <haley at ucar.edu>:
>>
>>> ​Dear Sebastien,
>>>
>>> In the future please post NCL questions / issues to ncl-talk at ucar.edu.
>>> The ncarg-talk at ucar.edu email list is for NCAR Graphics users, and is
>>> not an active group.
>>>
>>> http://mailman.ucar.edu/mailman/listinfo/ncl-talk
>>>
>>> ​Without having access to the dataset, it is hard for us to debug this
>>> problem. It would help, then, if you could provide more information about
>>> the variable, like what kind of metadata it has.
>>>
>>> Do you get any kind of error from ncl_filedump?
>>>
>>> Could you run the short NCL script below, and send me the output from
>>> running it, using both NCL V6.3.0 and V6.4.0, including any error messages:
>>>
>>> a = addfile("20122017_15.grb","r")
>>> csnow = a->CSNOW_GDS0_SFC
>>> printVarSummary(csnow)
>>> printMinMax(csnow,0)
>>> print(num(ismissing(csnow)))
>>>
>>> Finally, is there some place we can download this file, or a similar
>>> one,  from?
>>>
>>> Thanks,
>>>
>>> --Mary
>>>
>>> On Wed, Jan 3, 2018 at 1:49 AM, Sébastien POITEVIN <
>>> sebastien.poitevin at meteoconsult.com> wrote:
>>>
>>>> Hi all,
>>>>
>>>> When we read "Categorical Snow" with NCL 6.4.0 version (ncl_filedump -v
>>>> CSNOW_GDS0_SFC 20122017_15.grb or with 'PrintMinMax' command), we have
>>>> always null value (min and max value = 0)  whereas we have no problem when
>>>> we read the same grib file with the 6.3.0 version (min = 0 and max = 1).
>>>>
>>>> Grib files are produced by WRF-NMM (version V3.7.1) and UPPV3.0.
>>>>
>>>> Our system is "3.16.0-4-amd64 #1 SMP Debian 3.16.43-2+deb8u5
>>>> (2017-09-19) x86_64 GNU/Linux"
>>>>
>>>> Unfortunately I cannot send you a WRF grib file because it is too large.
>>>>
>>>> Thanks for your help.
>>>>
>>>> --
>>>>
>>>> _______________________________________________
>>>> ncarg-talk mailing list
>>>> ncarg-talk at ucar.edu
>>>> http://mailman.ucar.edu/mailman/listinfo/ncarg-talk
>>>>
>>>>
>>>
>>
>>
>> --
>>
>
>
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