[ncl-talk] Longitude Flip in ocean data
Arun Kumar Dwivedi
dwivedi.arunkumar at gmail.com
Tue Jan 19 21:28:59 MST 2016
Dear All,
As discussed earlier, We have uploaded our nc file and our script in the
ftp server. Our requirement is to plot a parameter for Atlantic and Indian
ocean (For eg -90W to 100E and from -50S to 50 N).. And our resultant
output is also attached where in the plot is only until 0E.
NOTE: We are taking our inputs from a dat file which is also attached here
(mom-ctrl-slc.dat)
Data File Name--Forecast201510040000.nc
Input control File Name --mom-ctrl-slc.dat
Script Name-- mom-slc.ncl
Our output Name-- mom_slc_TEMPNEW_2015100612UTC.png
Thanks & Regards
Arun Kumar Dwivedi,
Project Engineer - II
Computational Earth Science Group
CDAC, Pune - 411 007
Mob :09546189035
On Sat, Jan 16, 2016 at 2:13 AM, Mary Haley <haley at ucar.edu> wrote:
> Can you provide me with the data file so I can test this here? It looks
> like the longitude values should be flipping correctly, but I don't
> understand why you are getting values from -257.75 to 101.75.
>
> The longitude array must be monotonically increasing for this to work, I
> believe, but I want to check the array myself to see what's going on with
> it.
>
> If your file is too large, then if you could just write sst to the file by
> itself, and send me that, then I don't need anything else.
>
> You can write sst to a file using the following code:
>
>
> system("rm marytest.nc")
> mout = addfile("marytest.nc","c")
> mout->sst = sst
>
> You can upload the file to our ftp:
>
> http://www.ncl.ucar.edu/report_bug.shtml#HowToFTP
>
> or share it via Dropbox or Google Drive or something similar.
>
> Thanks,
>
> --Mary
>
>
>
> On Wed, Jan 13, 2016 at 12:40 AM, Arun Kumar Dwivedi <
> dwivedi.arunkumar at gmail.com> wrote:
>
>> Dear all,
>> Thank q for the response
>> In continuation to my above query the description is given below
>>
>> Our data is rectilinear data ( data is in rectangular matrix with
>> un-uniform spacing). '
>>
>> Our basic data structure is :
>>
>> Variable: sst
>> Type: float
>> Total Size: 4499840 bytes
>> 1124960 values
>> Number of Dimensions: 4
>> Dimensions and sizes: [T1 | 20] x [ZT_K1_1 | 1] x [YT_J | 178] x [XT_I
>> | 316]
>> Coordinates:
>> T1: [1005606..1005720]
>> ZT_K1_1: [ 2.5.. 2.5]
>> YT_J: [ -79.. 79]
>> XT_I: [ 1.. 359]
>> Number Of Attributes: 4
>> missing_value : -1e+34
>> _FillValue : -1e+34
>> long_name : SST
>> units : C
>>
>>
>> ****************************
>> Our actual problem is we need to plot longitude in the selected range for
>> eg -90W to 120E then it doesnt accept the -90W value since the longitude
>> array is from 0 to 360 , the plot comes from 0 to 120E only. (-ve values
>> not accepted.) . To solve this we used lonflip function so that our
>> longitude array changes from -180 to 180. but since it is un-uniform data ,
>> ***********************************
>> After LonFlip , it is
>>
>> Variable: sstnew
>> Type: float
>> Total Size: 4499840 bytes
>> 1124960 values
>> Number of Dimensions: 4
>> Dimensions and sizes: [T1 | 20] x [ZT_K1_1 | 1] x [YT_J | 178] x [XT_I
>> | 316]
>> Coordinates:
>> T1: [1005606..1005720]
>> ZT_K1_1: [ 2.5.. 2.5]
>> YT_J: [ -79.. 79]
>> XT_I: [-257.75..101.75]
>> Number Of Attributes: 5
>> missing_value : -1e+34
>> _FillValue : -1e+34
>> long_name : SST
>> units : C
>> lonFlip : longitude coordinate variable has been reordered via
>> lonFlip
>>
>> The longitude is originally from 0 to 360 and after LonFlip it is
>> -257.75..101.75... But when we are plotting in the longitude range (-90,
>> 120) it is coming only in the longitude range (-90, 101)
>>
>> So what would be the solution for our problem
>>
>>
>>
>> Thanks & Regards
>> Arun Kumar Dwivedi,
>> Project Engineer - II
>> Computational Earth Science Group
>> CDAC, Pune - 411 007
>> Mob :09546189035
>>
>> On Tue, Jan 12, 2016 at 7:44 PM, Mary Haley <haley at ucar.edu> wrote:
>>
>>> Arun,
>>>
>>> We need a little more information here. Is your data on a rectilinear
>>> grid? This function only works for rectilinear grids (grids represented by
>>> 1D lat/lon arrays).
>>>
>>> Did you look at your longitude values to make sure there are no issues
>>> with them before you do lonFlip?
>>>
>>> It would help if we could see a "printVarSummary" of the variable you
>>> are trying to call lonFlip on, and also any error messages.
>>>
>>> --Mary
>>>
>>>
>>> On Sun, Jan 10, 2016 at 11:10 PM, Arun Kumar Dwivedi <
>>> dwivedi.arunkumar at gmail.com> wrote:
>>>
>>>> Dear All,
>>>> I am working on ocean data (MOM and WAM) for global domain. I have
>>>> issues with longitude, when trying to plot in for particular region. For eg
>>>> if I want plot with Latitude 0 to 30 and Lon -40 to 100. Then it doesn't
>>>> recognize the value -40 in the longitude array.
>>>>
>>>> For this i have tried using LonFlip function, it works fine with
>>>> uniform grid but doesn't work with my data set which has varied grid
>>>> resolution (0.5,1 and 1.5).
>>>>
>>>>
>>>> Thanks & Regards
>>>> Arun Kumar Dwivedi,
>>>>
>>>>
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>>>
>>
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>
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