[ncl-talk] set_dimension_query
Adam Phillips
asphilli at ucar.edu
Thu Sep 14 09:39:08 MDT 2017
Hi Kunal,
It looks to me like your latitudes are flipped. You are setting up and
assigning your coordinate lat/lon variables in this coding:
nlat = 1200
nlon = 1200
lat = latGlobeFo(nlat, "lat", "latitude", "degrees_north")
lon = lonGlobeFo(nlon, "lon", "longitude", "degrees_east")
lat = lat(::-1)
lon = (/ lon - 180. /) ; subtract 180 from all values
lon&lon = lon ; update coordinates
var!0 = "lat" ; you can name these dimensions whatever you want..
var!1 = "lon"
var&lat = lat ; but make sure you refer to the correct named dimensions
var&lon = lon
Assuming I'm right on your latitudes being the issue, one of the following
two modifications should work:
Delete this line:
lat = lat(::-1)
If the above doesn't fix it, try this:
Change this:
lat = lat(::-1)
to this:
lat = lat(::-1)
lat&lat = lat
If you continue to have issues please respond to ncl-talk.
Adam
On Wed, Sep 13, 2017 at 12:35 PM, Kunal Bali <kunal.bali9 at gmail.com> wrote:
>
> For direct output as a netcdf format, I used the script given below. It
> produced the netcdf file easily. But the netcdf file and original hdf file
> both showing the different results. The data pattern is shifted. I mean it
> may be related to the lat lon position. please see the attached file, you
> will understand. And please let me know which one is correct.
>
> ;----------------------------------------------------------------------
>
> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"
> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl"
> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"
>
> begin
> ;---Read data
> a = addfile("/media/Local Disk/NPL/MODIS_FPC/MAIACTAOT.
> h00v02.20000570505.hdf","r")
> var = short2flt(a->Optical_Depth_055(:,:))
> ; short2flt(a[:]->noxfire)
> nlat = 1200
> nlon = 1200
> lat = latGlobeFo(nlat, "lat", "latitude", "degrees_north")
> lon = lonGlobeFo(nlon, "lon", "longitude", "degrees_east")
> lat = lat(::-1)
> lon = (/ lon - 180. /) ; subtract 180 from all values
> lon&lon = lon ; update coordinates
>
> var!0 = "lat" ; you can name these dimensions whatever you
> want..
> var!1 = "lon"
> var&lat = lat ; but make sure you refer to the correct named
> dimensions
> var&lon = lon
>
> system("/bin/rm -f simple.nc")
> ncdf = addfile("simple.nc" ,"c") ; open output netCDF file
>
> ;===================================================================
> ; create global attributes of the file (optional)
> ;===================================================================
> fAtt = True ; assign file attributes
> fAtt at title = "NCL Simple Approach to netCDF Creation"
> fAtt at source_file = "original-file.nc"
> fAtt at Conventions = "None"
> fAtt at creation_date = systemfunc ("date")
> fileattdef( ncdf, fAtt ) ; copy file attributes
>
> ;===================================================================
> ; make time an UNLIMITED dimension; recommended for most applications
> ;===================================================================
> filedimdef(ncdf,"time",-1,True)
> ncdf->var = var
>
> end
>
>
>
>
> Kunal Bali
>
>
>
>
>
>
> On Wed, Sep 13, 2017 at 11:27 PM, Kunal Bali <kunal.bali9 at gmail.com>
> wrote:
>
>> No problem, I sorted out.
>>
>> Just changed short to float.
>>
>> Kunal Bali
>> Research Scholar
>> Radio & Atmospheric Science Division
>> CSIR - National Physical Laboratory
>> New Delhi - 110012
>> India
>>
>>
>>
>>
>>
>> On Wed, Sep 13, 2017 at 11:24 PM, Kunal Bali <kunal.bali9 at gmail.com>
>> wrote:
>>
>>> Thanks for providing this information.
>>>
>>> Also, I would like to mention that when I plot this data. The values are
>>> not in the domain. I mean the real values lie in-between 0 to 1 but here it
>>> is reaching to 400.
>>>
>>> So, how to correct the values?
>>>
>>> Description of the variable is
>>>
>>> short Optical_Depth_055(YDim=1200, XDim=1200);
>>> :long_name = "AOT at 0.55 micron";
>>> :scale_factor = 0.001; // double
>>> :add_offset = 0.0; // double
>>> :unit = "None";
>>> :_FillValue = -28672S; // short
>>> :valid_range = -100S, 5000S; // short
>>>
>>>
>>>
>>>
>>> Kunal Bali
>>>
>>>
>>>
>>>
>>>
>>>
>>> On Wed, Sep 13, 2017 at 10:28 PM, Adam Phillips <asphilli at ucar.edu>
>>> wrote:
>>>
>>>> Hi Kunal,
>>>> Yes, clicking on the output netCDF link from the Applications page:
>>>> http://www.ncl.ucar.edu/Applications/o-netcdf.shtml
>>>> I would recommend following the inefficient method #1. Unless you are
>>>> writing a file with many large variables, the inefficient method works just
>>>> fine.
>>>> http://www.ncl.ucar.edu/Applications/method_1.shtml
>>>> Good luck,
>>>> Adam
>>>>
>>>> On Wed, Sep 13, 2017 at 10:25 AM, Kunal Bali <kunal.bali9 at gmail.com>
>>>> wrote:
>>>>
>>>>> Thank you so much, it worked
>>>>>
>>>>> I want to know one more thing.
>>>>> After rearranging the dimensions can we now convert (or write) this
>>>>> arranged file into netcdf format?
>>>>>
>>>>>
>>>>>
>>>>> Kunal Bali
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> On Wed, Sep 13, 2017 at 8:55 PM, Adam Phillips <asphilli at ucar.edu>
>>>>> wrote:
>>>>>
>>>>>> Hi Kunal,
>>>>>> I think you just need to rearrange the order of your lines and tweak
>>>>>> a couple of lines. As the error message states, lat is not defined in your
>>>>>> 3rd line and you are referring to it as if it is.Try this:
>>>>>> a = addfile("/media/Local Disk/NPL/MODIS_FPC/MAIACTAOT.h
>>>>>> 00v02.20000570505.hdf","r")
>>>>>> var = a->Optical_Depth_055(:,:)
>>>>>> nlat = 1200
>>>>>> nlon = 1200
>>>>>> lat = latGlobeFo(nlat, "lat", "latitude", "degrees_north")
>>>>>> lon = lonGlobeFo(nlon, "lon", "longitude", "degrees_east")
>>>>>> lat = lat(::-1)
>>>>>> lon = (/ lon - 180. /) ; subtract 180 from all values
>>>>>> lon&lon = lon ; update coordinates
>>>>>>
>>>>>> var!0 = "lat" ; you can name these dimensions whatever you want..
>>>>>> var!1 = "lon"
>>>>>> var&lat = lat ; but make sure you refer to the correct named
>>>>>> dimensions
>>>>>> var&lat = lon
>>>>>> ;var&XDim_grid1km = lat
>>>>>> ;var&YDim_grid1km = lon
>>>>>>
>>>>>> If you have any further questions please respond to the ncl-talk
>>>>>> email list.
>>>>>> Adam
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Wed, Sep 13, 2017 at 8:38 AM, Kunal Bali <kunal.bali9 at gmail.com>
>>>>>> wrote:
>>>>>>
>>>>>>> Dear NCL
>>>>>>>
>>>>>>> I have a file with the variable summary. The dimensions are in 2D.
>>>>>>>
>>>>>>> ncl 2> printVarSummary(var)
>>>>>>>
>>>>>>> Variable: var
>>>>>>> Type: short
>>>>>>> Total Size: 2880000 bytes
>>>>>>> 1440000 values
>>>>>>> Number of Dimensions: 2
>>>>>>> Dimensions and sizes: [*YDim_grid1km | 1200] x [XDim_grid1km |
>>>>>>> 1200]*
>>>>>>> Coordinates:
>>>>>>> Number Of Attributes: 7
>>>>>>> long_name : AOT at 0.55 micron
>>>>>>> scale_factor : 0.001
>>>>>>> add_offset : 0
>>>>>>> unit : None
>>>>>>> _FillValue : -28672
>>>>>>> valid_range : ( -100, 5000 )
>>>>>>> hdf_name : Optical_Depth_055
>>>>>>>
>>>>>>>
>>>>>>> I am trying to read the dimensions of this file as
>>>>>>>
>>>>>>> begin
>>>>>>> ;---Read data
>>>>>>> a = addfile("/media/Local Disk/NPL/MODIS_FPC/MAIACTAOT.h
>>>>>>> 00v02.20000570505.hdf","r")
>>>>>>>
>>>>>>> var = a->Optical_Depth_055(:,:)
>>>>>>>
>>>>>>> var&XDim_grid1km = lat
>>>>>>> var&YDim_grid1km = lon
>>>>>>>
>>>>>>> nlat = 1200
>>>>>>> nlon = 1200
>>>>>>> lat = latGlobeFo(nlat, "lat", "latitude",
>>>>>>> "degrees_north")
>>>>>>> lon = lonGlobeFo(nlon, "lon", "longitude", "degrees_east")
>>>>>>> lat = lat(::-1)
>>>>>>> lon = (/ lon - 180. /) ; subtract 180 from all values
>>>>>>> lon&lon = lon ; update coordinates
>>>>>>>
>>>>>>>
>>>>>>> var!0 = "lat"
>>>>>>> var!1 = "lon"
>>>>>>>
>>>>>>>
>>>>>>> But the error appeared as
>>>>>>> *fatal:Variable (lat) is undefined*
>>>>>>>
>>>>>>>
>>>>>>> So, could anyone please let me know that how to read dimension of
>>>>>>> this file.
>>>>>>>
>>>>>>> Thank You
>>>>>>>
>>>>>>>
>>>>>>> Regards
>>>>>>> Kunal Bali
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> _______________________________________________
>>>>>>> ncl-talk mailing list
>>>>>>> ncl-talk at ucar.edu
>>>>>>> List instructions, subscriber options, unsubscribe:
>>>>>>> http://mailman.ucar.edu/mailman/listinfo/ncl-talk
>>>>>>>
>>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>> Adam Phillips
>>>>>> Associate Scientist, Climate and Global Dynamics Laboratory, NCAR
>>>>>> www.cgd.ucar.edu/staff/asphilli/ 303-497-1726 <(303)%20497-1726>
>>>>>>
>>>>>> <http://www.cgd.ucar.edu/staff/asphilli>
>>>>>>
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> ncl-talk mailing list
>>>>> ncl-talk at ucar.edu
>>>>> List instructions, subscriber options, unsubscribe:
>>>>> http://mailman.ucar.edu/mailman/listinfo/ncl-talk
>>>>>
>>>>>
>>>>
>>>>
>>>> --
>>>> Adam Phillips
>>>> Associate Scientist, Climate and Global Dynamics Laboratory, NCAR
>>>> www.cgd.ucar.edu/staff/asphilli/ 303-497-1726 <(303)%20497-1726>
>>>>
>>>> <http://www.cgd.ucar.edu/staff/asphilli>
>>>>
>>>
>>>
>>
>
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>
--
Adam Phillips
Associate Scientist, Climate and Global Dynamics Laboratory, NCAR
www.cgd.ucar.edu/staff/asphilli/ 303-497-1726
<http://www.cgd.ucar.edu/staff/asphilli>
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