Ok, thanks all for checking it out. I will put it on hold until its clear
if its in error, etc. I think its a simple fix if we need to support it.
John
On Wed, Jan 28, 2015 at 5:38 PM, Bonny Strong - NOAA Affiliate <
bonny.strong@xxxxxxxx> wrote:
> For info, I spoke briefly to Ning Wang about this. He can talk to NCEP
> software people he works with, but this isn't his highest priority, and
> this may take some time.
>
> I wonder if there is a more formal route for a request-for-change that we
> could follow to get this change made officially. Bob, any experience with
> this?
>
> On Wed, Jan 28, 2015 at 5:21 PM, Bob Lipschutz - NOAA Affiliate <
> robert.c.lipschutz@xxxxxxxx> wrote:
>
>> Hi John. Thanks for the ping. No, I don't have access to other sample
>> GRIB files with this property. The only progress we've made is that we had
>> an exchange with a fellow in the NCEP marine modeling group (EMC/MMAB) who
>> said this about their sea ice products:
>>
>> The 1/8th degree grid never went to production. I'm amazed that there
>>> was a table entry for it. The high resolution ice grids in production are
>>> number 171, 172, 173 -- northern hemisphere, southern hemisphere, global,
>>> respectively. The hemispheric grids are 1/30 bedient, and global is 1/12th
>>> degree.
>>
>>
>> This leads me to believe that the scanMode setting in the grid 174
>> definition is in error, and that 174 probably had never really been used
>> until we came along. We need to talk to the maintainers of the NCEP tables,
>> and see if we can get it corrected.
>>
>> Thanks again for your support on this!
>>
>> -Bob
>>
>>
>> On Wed, Jan 28, 2015 at 11:52 PM, John Caron <caron@xxxxxxxx> wrote:
>>
>>> Hi Bob:
>>>
>>> Any word from NCEP on this issue? Or sample files that already use
>>> scanmode 64?
>>>
>>> John
>>>
>>> On Wed, Jan 14, 2015 at 10:30 AM, Bob Lipschutz - NOAA Affiliate <
>>> robert.c.lipschutz@xxxxxxxx> wrote:
>>>
>>>> John,
>>>>
>>>> Thanks for looking at this. Sorry, I don't have any particular
>>>> recommendation here. The grid specification does seem odd and inconsistent
>>>> with other domains with scanMode=64 that give south-to-north corner
>>>> coordinates. It's also inconsistent with the similar 1/12th degree '173'
>>>> grid, which has scanMode=0 and north-to-south corners. We will check with
>>>> NCEP to see if there's an error in the table, but it's not a new entry and
>>>> ostensibly used by someone out there (it's described as a Sea Ice grid)...
>>>>
>>>> Thanks again,
>>>>
>>>> -Bob
>>>>
>>>> On Wed, Jan 14, 2015 at 1:14 AM, Bonny Strong - NOAA Affiliate <
>>>> bonny.strong@xxxxxxxx> wrote:
>>>>
>>>>> John, I don't have Bob's expertise, but I know that during discussions
>>>>> here at GSD trying to figure this out, one developer gave his opinion that
>>>>> the lats of the first and last point were unrelated related to the scan
>>>>> direction. Bob may wish to add to that tomorrow.
>>>>>
>>>>> Bonny
>>>>>
>>>>> On Tue, Jan 13, 2015 at 6:07 PM, John Caron <caron@xxxxxxxx> wrote:
>>>>>
>>>>>> Hi Bob:
>>>>>>
>>>>>> Thanks for reporting this problem. Im looking at it now. Do you have
>>>>>> any idea how these various parameters interact? They have first lat in
>>>>>> north, last lat in south, but a positive Dj. Then with scanMode 64, they
>>>>>> say "Points of first row or column scan in the +j (+y) direction". Seems
>>>>>> overspecified with the possibility of inconsistent results. Im looking
>>>>>> though my data samples now to see if I can detect if there is are
>>>>>> problems,
>>>>>> but im not exactly sure what combinations should be legal. Any thoughts?
>>>>>>
>>>>>> heres my dump on your record:
>>>>>>
>>>>>> 47: La1 -
>>>>>> latitude of first grid point == 89938000
>>>>>> 56: La2 -
>>>>>> latitude of last grid point == -89938000
>>>>>> 68:
>>>>>> Dj - j direction increment == 125000
>>>>>> 72:
>>>>>> Scanning mode == 64
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Mon, Jan 12, 2015 at 4:02 PM, Bob Lipschutz - NOAA Affiliate <
>>>>>> Robert.C.Lipschutz@xxxxxxxx> wrote:
>>>>>>
>>>>>>>
>>>>>>> Java NetCDF Folks,
>>>>>>>
>>>>>>> We have recently begun generating global 1/8 degree GRIB files
>>>>>>> using NCEP's grid 174 definition (
>>>>>>> http://www.nco.ncep.noaa.gov/pmb/docs/on388/tableb.html#GRID174).
>>>>>>>
>>>>>>> Following that definition, we are setting the value of scanMode to
>>>>>>> 64, which
>>>>>>> per GRIB2 Table 3.4 indicates "points scan in the +j direction", and
>>>>>>> so filling
>>>>>>> the data arrays from south to north. However, the java-netCDF
>>>>>>> package (v4.5)
>>>>>>> does not seem to handle the scanMode flag properly, and consequently
>>>>>>> our
>>>>>>> grids appear flipped on display. Meanwhile, I understand that NCL
>>>>>>> does handle
>>>>>>> the data mapping correctly, from which we conclude that java-netCDF
>>>>>>> is has a
>>>>>>> problem with this grid definition.
>>>>>>>
>>>>>>> As a work-around, we will set scanMode to 0 and write from north to
>>>>>>> south,
>>>>>>> which will fix the problem for us. But, we'd also hope to have the
>>>>>>> tools work
>>>>>>> correctly, too so that we can use the NCEP's grid as specified --
>>>>>>> which
>>>>>>> admittedly is strange in that it list the corner lons from north to
>>>>>>> south.
>>>>>>>
>>>>>>> I've posted a sample GRIB2 file and resulting flipped image here:
>>>>>>>
>>>>>>> ftp://aftp.fsl.noaa.gov/divisions/its/bob/grid174_scanmode_64_example.grb2
>>>>>>> ftp://aftp.fsl.noaa.gov/divisions/its/bob/flipped_174grid.jpg
>>>>>>>
>>>>>>> FWIW, here is the output from the (v4.3) Grib2Dump utility on that
>>>>>>> data file:
>>>>>>>
>>>>>>> Header : GRIB2
>>>>>>> Discipline : 0 Meteorological
>>>>>>> products
>>>>>>> GRIB Edition : 2
>>>>>>> GRIB length : 2808735
>>>>>>> Originating Center : 59 The NOAA Forecast
>>>>>>> Systems Laboratory
>>>>>>> Originating Sub-Center : 0
>>>>>>> Significance of Reference Time : 1 Start of forecast
>>>>>>> Reference Time : 2015-01-08T00:00:00Z
>>>>>>> Product Status : 0 Operational products
>>>>>>> Product Type : 1 Forecast products
>>>>>>> Number of data points : 4147200
>>>>>>> Grid Name : 0 Latitude_Longitude
>>>>>>> Grid Shape: 0 Earth spherical
>>>>>>> with radius = 6,367,470 m
>>>>>>> Number of points along parallel: 2880
>>>>>>> Number of points along meridian: 1440
>>>>>>> Basic angle : 0
>>>>>>> Subdivisions of basic angle: 0
>>>>>>> Latitude of first grid point : 89.938
>>>>>>> Longitude of first grid point : 0.062
>>>>>>> Resolution & Component flags : 48
>>>>>>> Winds : True
>>>>>>> Latitude of last grid point : -89.938
>>>>>>> Longitude of last grid point : 359.938
>>>>>>> i direction increment : 0.125
>>>>>>> j direction increment : 0.125
>>>>>>> Grid Units : degrees
>>>>>>> Scanning mode : 64
>>>>>>> Product Definition : 0
>>>>>>> Analysis/forecast at horizontal level/layer at a point in time
>>>>>>> Parameter Category : 0 Temperature
>>>>>>> Parameter Name : 0 Temperature
>>>>>>> Parameter Units : K
>>>>>>> Generating Process Type : 2 Forecast
>>>>>>> ForecastTime : 240
>>>>>>> First Surface Type : 1 Ground or water
>>>>>>> surface
>>>>>>> First Surface value : 0.0
>>>>>>> Second Surface Type : 255 Missing
>>>>>>> Second Surface value : 0.0
>>>>>>>
>>>>>>> Thanks for any insights on this issue!
>>>>>>>
>>>>>>> Bob Lipschutz
>>>>>>> NOAA/ESRL/Global Systems Division
>>>>>>> IT Services/Data Services Group
>>>>>>>
>>>>>>>
>>>>>>> _______________________________________________
>>>>>>> netcdf-java mailing list
>>>>>>> netcdf-java@xxxxxxxxxxxxxxxx
>>>>>>> For list information or to unsubscribe, visit:
>>>>>>> http://www.unidata.ucar.edu/mailing_lists/
>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> Bonny Strong
>>>>> NOAA Affiliate
>>>>> 303 497-3936
>>>>>
>>>>
>>>>
>>>
>>
>
>
> --
> Bonny Strong
> NOAA Affiliate
> 303 497-3936
>
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