[ncl-talk] hdf5 file in ncl

Dennis Shea shea at ucar.edu
Wed Nov 15 15:44:17 MST 2017


Not quite sure what was sent:

As noted within the original HDF-EOS file

filename:       MYDAODHD.A2017305.0000.061.NRT
path:   MYDAODHD.A2017305.0000.061.NRT.hdf
   file global attributes:
      HDFEOSVersion : *HDFEOS_*V2.19
      StructMetadata_0 : GROUP=

*SwathStructure   <====*=====

There are numerous examples of swath data being plotted on NCL's
Applications page:

   http://www.ncl.ucar.edu/Applications/HDF.shtml

The attached is a variation on one of the examples.

=====
I strongly sugest that you always carefully look at your data. I used one
function which I have always found useful for looking at a variables.
Satellite swath data can have outliers so knowledge of the distribution os
data is important.

Good Luck

On Wed, Nov 15, 2017 at 11:58 AM, Debasish Hazra <debasish.hazra5 at gmail.com>
wrote:

> Thanks Mary. I am able to use the example to plot the variable.
>
> Debasish
>
> On Wed, Nov 15, 2017 at 12:06 PM, Adam Phillips <asphilli at ucar.edu> wrote:
>
>> Hi Debasish,
>> See the first station data example here:
>> http://www.ncl.ucar.edu/Applications/station.shtml
>> Hope that helps!
>> Adam
>>
>> On Wed, Nov 15, 2017 at 8:33 AM, Debasish Hazra <
>> debasish.hazra5 at gmail.com> wrote:
>>
>>> Thanks Mary, adding "he2" suffix at the end helped. I have another
>>> quaetion  to ask on this, how to assign 1 dimesnional lat and lon to the
>>> variable field ? So far, I have :
>>>
>>>             oc_aod1 = w->Aerosol_Optical_Depth_Ocean_Aqua_AOD
>>>
>>>             lat1 = w->Latitude_Ocean_Aqua_AOD
>>>             lon1 = w->Longitude_Ocean_Aqua_AOD
>>>
>>> PrintVarSummary of them :
>>>
>>> Variable: oc_aod1
>>> Type: float
>>> Total Size: 15116 bytes
>>>             3779 values
>>> Number of Dimensions: 1
>>> Dimensions and sizes:   [Nobs_Ocean_Aqua_AOD | 3779]
>>> Coordinates:
>>> Number Of Attributes: 2
>>>   _FillValue :  -999
>>>   hdfeos_name : Aerosol_Optical_Depth
>>> Variable: lat1
>>> Type: float
>>> Total Size: 15116 bytes
>>>             3779 values
>>> Number of Dimensions: 1
>>> Dimensions and sizes:   [Nobs_Ocean_Aqua_AOD | 3779]
>>> Coordinates:
>>> Number Of Attributes: 4
>>>   _FillValue :  -999
>>>   hdfeos_name : Latitude
>>>   units :       degrees_north
>>>   long_name :   latitude
>>> Variable: lon1
>>> Type: float
>>> Total Size: 15116 bytes
>>>             3779 values
>>> Number of Dimensions: 1
>>> Dimensions and sizes:   [Nobs_Ocean_Aqua_AOD | 3779]
>>> Coordinates:
>>> Number Of Attributes: 4
>>>   _FillValue :  -999
>>>   hdfeos_name : Longitude
>>>   units :       degrees_east
>>>   long_name :   longitude
>>>
>>> Variable has one dimension, how do I make lat/lon grid for visualization
>>> ?
>>>
>>> Thanks.
>>> Debasish
>>>
>>> On Tue, Nov 14, 2017 at 5:57 PM, Mary Haley <haley at ucar.edu> wrote:
>>>
>>>> Hi Debasish,
>>>>
>>>> This is an HDF-EOS2 file, which you can see if you do an ncl_filedump
>>>> on the file and look at the top part of the output:
>>>>
>>>> Variable: f
>>>> Type: file
>>>> filename:       MYDAODHD.A2017305.0000.061.NRT
>>>> path:   MYDAODHD.A2017305.0000.061.NRT.hdf
>>>>    file global attributes:
>>>>       HDFEOSVersion : HDFEOS_V2.19
>>>>
>>>> Try adding ".he2" to the end of the filename in your script. This will
>>>> tell NCL to try opening the file as an HDF-EOS2 file:
>>>>
>>>>  diri = "./November2017/1/"
>>>>  fili = "MYDAODHD.A2017305.0000.061.NRT.hdf.*he2*"
>>>> ​ ​
>>>> pthi = diri+fili
>>>>  w = addfile(pthi,"r")
>>>>
>>>> It is not necessary to rename the file itself. The "addfile" command
>>>> will first look for a file called "MYDAODHD.A2017305.0000.061.NRT.hdf.he2",
>>>> and if it can't find that, it will look for the file "
>>>> MYDAODHD.A2017305.0000.061.NRT.hdf", but will try to open it as an
>>>> HDF-EOS2 file.
>>>>
>>>> Once you do this, the
>>>> ​file will look much more reasonable.
>>>>
>>>> --Mary
>>>>
>>>> On Tue, Nov 14, 2017 at 2:20 PM, Debasish Hazra <
>>>> debasish.hazra5 at gmail.com> wrote:
>>>>
>>>>> Hi,
>>>>>
>>>>> I am trying to read attached HDF5 file using ncl v6.4 but not able to
>>>>> extract data attributes from "Group".
>>>>>
>>>>>  diri = "./November2017/1/"
>>>>>      fili = "MYDAODHD.A2017305.0000.061.NRT.hdf"
>>>>>
>>>>>             pthi = diri+fili
>>>>>             w = addfile(pthi,"r")
>>>>>             mod1 = "Aerosol_Optical_Depth"
>>>>>             Latitude = "Latitude"
>>>>>             Longitude = "Longitude"
>>>>>             print(mod1)
>>>>>              gp = w->GeoField
>>>>>
>>>>> Variable: mod1
>>>>> Type: string
>>>>> Total Size: 8 bytes
>>>>>             1 values
>>>>> Number of Dimensions: 1
>>>>> Dimensions and sizes:   [1]
>>>>> Coordinates:
>>>>> (0)     Aerosol_Optical_Depth
>>>>> fatal:["Execute.c":6397]:variable (GeoField) is not in file (w)
>>>>>
>>>>> Not sure how to proceed with that. Any help is appreciated.
>>>>>
>>>>> Debasish
>>>>>
>>>>> _______________________________________________
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>>>>> ncl-talk at ucar.edu
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>>>>>
>>>>>
>>>>
>>>
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>>
>>
>> --
>> 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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