[ncl-talk] Pixel to Lat/Lon

[Ipsita Putatunda]

Hi Mary,
 If I plot in "RasterFill" mode then only the plot is appearing, not even I
set "AreaFill" or "CellFill".
The plot is appearing something like fractured, not a smoothed one (even
though I put smoothing), I don't know why it is like so.

Thanks in advance,
Ipsita

On Fri, Jul 14, 2017 at 11:34 AM, Ipsita Putatunda <
ipsita.putatunda at gmail.com> wrote:

> Hi Mary,
>  I have uploaded my data file with my scripts through ftp.
>
> Ipsita
>
> On Fri, Jul 14, 2017 at 2:51 AM, Dennis Shea <shea at ucar.edu> wrote:
>
>> IMHO: The script is working correctly. However, there is a mismatch
>> between the
>> the user's VERY high resolution (0.15 degrees) 'target grid' and the
>> resolution of the swath data points.
>>
>> re:
>>
>>  nlat=1200
>>  nlon=2400
>>
>> defines a grid with spacing 0.15 degrees. VERY high resolution
>>
>> ====
>>
>> I have no idea what the rationale for the '400' used for GBIN and GKNTwas
>> based upon.
>>
>>  GBIN  = new ( (/400,nlon/), float )
>>  GKNT = new ( (/400,nlon/), integer )
>>
>> =====
>>
>> The binning algorithm looks at each swath lat/lon location. It finds the
>> target grid box that 'surrounds'  the current swath lat/lon location.
>>
>> If there are target grid boxes which do not surround the swath grid
>> poins, then they are returned as missing (_FillValue). Hence, the
>> 'fractured' look of the plot.
>>
>> D
>>
>>
>>
>>
>>
>> On Thu, Jul 13, 2017 at 2:52 PM, Mary Haley <haley at ucar.edu> wrote:
>>
>>> Hi Ipsita,
>>>
>>> I'm not sure what you mean by " even though the plot is not coming with
>>> a clear contours. "
>>>
>>> The plot you included doesn't look particularly wrong, so can you
>>> explain what you were expecting?
>>>
>>> The script you attached does not include any plotting code, so I can't
>>> help you much there.
>>>
>>> Can you be more specific about the problem?  Also, it would really help
>>> if you can provide the data and the plotting script in the usual way (ftp).
>>>
>>> Thanks,
>>>
>>> --Mary
>>>
>>>
>>>
>>>
>>> On Thu, Jul 13, 2017 at 7:04 AM, Ipsita Putatunda <
>>> ipsita.putatunda at gmail.com> wrote:
>>>
>>>> Thank you Dave for your suggestions. I tried to plot the data, but it
>>>> is coming only if I plot setting resource "RasterFill", and even though the
>>>> plot is not coming with a clear contours. Don't know where I am making
>>>> mistake. I tried to regrid the data using "triple2grid" but then all the
>>>> values are coming undefined. I am attaching herewith my script and the
>>>> figure I have got after plotting. Any help will be appreciated.
>>>> Thanks in advance.
>>>>
>>>> Ipsita
>>>>
>>>>
>>>> On Thu, Jul 13, 2017 at 4:19 AM, Dave Allured - NOAA Affiliate <
>>>> dave.allured at noaa.gov> wrote:
>>>>
>>>>> Ipsita,
>>>>>
>>>>> This HDF5 file has coordinate arrays Colatitude and Longitude.  The
>>>>> units of each are degrees, not pixels.  However, please notice two
>>>>> anomalies:
>>>>>
>>>>> 1.  The coordinates are packed with an unusual scale/offset packing
>>>>> scheme.  The packing parameters are in attributes Scale_Factor and
>>>>> Add_Offset, which are not CF standard attributes.  However, the intent is
>>>>> fairly clear.  To unpack each coordinate value, just multiply by the
>>>>> Scale_Factor.
>>>>>
>>>>> The Add_Offset's are zero in this case, and can therefore be ignored.
>>>>> That is good, so that we do not have to worry about whether the offset
>>>>> would be applied before or after the scale factor.
>>>>>
>>>>> This will produce colatitudes in the normal range 60 to 120 degrees,
>>>>> and longitudes in the normal range 0 to 360 degrees.
>>>>>
>>>>> 2.  I assume that the colatitudes conform to the current definition on
>>>>> Wikipedia.  You might confirm this with the data provider, if you wish.
>>>>> This definition is the number of degrees southward from the north pole.
>>>>> The colatitude values unpacked are in the range 60 to 120 degrees, which
>>>>> translate to 30 north to 30 south in normal latitude units.
>>>>>
>>>>> --Dave
>>>>>
>>>>>
>>>>> On Wed, Jul 12, 2017 at 12:08 AM, Ipsita Putatunda <
>>>>> ipsita.putatunda at gmail.com> wrote:
>>>>>
>>>>>> The Latitude (here Colatitude) and Longitude data are in pixels which
>>>>>> is -30 to 30 degree and 0 to 360 degree. Please find the file I am
>>>>>> attaching herewith.
>>>>>>
>>>>>> Ipsita
>>>>>>
>>>>>> On Tue, Jul 11, 2017 at 10:30 PM, Dave Allured - NOAA Affiliate <
>>>>>> dave.allured at noaa.gov> wrote:
>>>>>>
>>>>>>> Ipsita,
>>>>>>>
>>>>>>> How is your input data georeferenced?  Does the input file include
>>>>>>> coordinate variables?  That is the most common way to get lats and lons for
>>>>>>> individual pixels.
>>>>>>>
>>>>>>> --Dave
>>>>>>> (Please reply to the mailing list.)
>>>>>>>
>>>>>>>
>>>>>>> On Tue, Jul 11, 2017 at 12:22 AM, Ipsita Putatunda <
>>>>>>> ipsita.putatunda at gmail.com> wrote:
>>>>>>>
>>>>>>>> Dear NCL users,
>>>>>>>>   I need help in converting pixels to Lat/Lon grid. Is there any
>>>>>>>> function or way in ncl for doing this operation? Please suggest.
>>>>>>>>
>>>>>>>> Thanks in advance,
>>>>>>>> Ipsita
>>>>>>>>
>>>>>>>
>>>>
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