[ncl-talk] Pixel to Lat/Lon

[Ipsita Putatunda]

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
>>>>
>>>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mailman.ucar.edu/pipermail/ncl-talk/attachments/20170713/490b640c/attachment.html 
-------------- next part --------------
A non-text attachment was scrubbed...
Name: SCR.ncl
Type: application/octet-stream
Size: 4297 bytes
Desc: not available
Url : http://mailman.ucar.edu/pipermail/ncl-talk/attachments/20170713/490b640c/attachment.obj 
-------------- next part --------------
A non-text attachment was scrubbed...
Name: xt.png
Type: image/png
Size: 155589 bytes
Desc: not available
Url : http://mailman.ucar.edu/pipermail/ncl-talk/attachments/20170713/490b640c/attachment.png