[ncl-talk] Wrong values getting on contour plot

Barry Lynn barry.h.lynn at gmail.com
Thu Jun 4 11:33:22 MDT 2020 

Yes, I understand that.  However, you are subsetting a single time step
over the sub set of data.

Are you subsetting one time step on purpose?

What was the results of the printVarSummary of f?

You need to know what your data is before you can go much further.

Barry

On Thu, Jun 4, 2020 at 8:27 PM Arathy RP <arathyrparathy at gmail.com> wrote:

> And also I need minimum value for subset variable f and not global
> variable f.
>
> On Thu, Jun 4, 2020, 10:56 PM Arathy RP <arathyrparathy at gmail.com> wrote:
>
>> And also I want the minimum value of subset variable f not from global
>> variable f.
>>
>> On Thu, Jun 4, 2020, 10:50 PM Arathy RP <arathyrparathy at gmail.com> wrote:
>>
>>> I am not ploting for only onw timestep. I need a plot of time series.
>>>
>>> On Thu, Jun 4, 2020, 10:45 PM Barry Lynn <barry.h.lynn at gmail.com> wrote:
>>>
>>>> Hi Arathy:
>>>>
>>>> Are you aware that you (most likely) subsetting one time step of the
>>>> data?  Don't you need a time series?  I am not sure you are mapping the
>>>> right parameter (f) -- but that is another issue.
>>>>
>>>> Instead of that, subset the data over lat/lon you want this way:
>>>>
>>>> f=data->MSL_GDS0_SFC(:,:,:)(or leave out all (:,:,:).
>>>>
>>>>
>>>> Then,
>>>>
>>>>
>>>> use the min command to find the minimum pressure within the subsetted
>>>> data set.
>>>>
>>>> https://www.ncl.ucar.edu/Document/Functions/Built-in/min.shtml
>>>>
>>>> You can use:
>>>>
>>>> https://www.ncl.ucar.edu/Document/Functions/Built-in/minind.shtml
>>>>
>>>> to find the location of the minimum pressure within the data set.
>>>>
>>>> but first use:
>>>>
>>>> https://www.ncl.ucar.edu/Document/Functions/Built-in/onedtond.shtml
>>>>
>>>> Just follow Example 2 or 3 on the minind page above.
>>>>
>>>> (below)
>>>>
>>>> *Example 2*
>>>>
>>>> Find the index of the minimum value in a multi-dimensional array.
>>>>
>>>> ;---Create a dummy 2 x 2 x 4 array.
>>>>   a = (/(/(/1,2,3,4/), (/5,6,7,8/)/), (/(/9,1,9,8/),(/7,6,1,4/)/)/)
>>>>
>>>> ;---Convert to 1D
>>>>   a1D      = *ndtooned* <https://www.ncl.ucar.edu/Document/Functions/Built-in/ndtooned.shtml>(a)
>>>>   dsizes_a = *dimsizes* <https://www.ncl.ucar.edu/Document/Functions/Built-in/dimsizes.shtml>(a)
>>>>
>>>> ;---Resolve the 1D indices back to their original 3D array.
>>>>   indices  = *ind_resolve* <https://www.ncl.ucar.edu/Document/Functions/Built-in/ind_resolve.shtml>(*minind*(a1D),dsizes_a)
>>>>   *print* <https://www.ncl.ucar.edu/Document/Functions/Built-in/print.shtml>(indices)
>>>>
>>>> *Example 3*
>>>>
>>>> Find the latitude and longitude location of the minimum value in a two
>>>> dimensional array.
>>>>
>>>> ;---X is a two dimensional array dimensioned lat x lon
>>>>   dims = *dimsizes* <https://www.ncl.ucar.edu/Document/Functions/Built-in/dimsizes.shtml>(X)
>>>>   x1d = *ndtooned* <https://www.ncl.ucar.edu/Document/Functions/Built-in/ndtooned.shtml>(X)      ; convert 2D array to 1D for use in minind
>>>>   inds = *ind_resolve* <https://www.ncl.ucar.edu/Document/Functions/Built-in/ind_resolve.shtml>(*minind* (x1d), dims)    ; convert 1D array back to 2D
>>>>   ilat = inds(0,0)        ; select the latitude index where the X array is at its' minimum
>>>>   ilon = inds(0,1)        ; select the longitude index where the X array is at its' minimum
>>>>   lat_min = X&lat(ilat)   ; insert the latitude index into the lat coordinate variable
>>>>   lon_min = X&lon(ilon)   ; insert the longitude index into the lon coordinate variable
>>>>   *print* <https://www.ncl.ucar.edu/Document/Functions/Built-in/print.shtml>("Minimum value located at "+lat_min+", "+lon_min)
>>>>
>>>>
>>>> to convert to a 1 dimensional array for the minind above.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> On Thu, Jun 4, 2020 at 6:17 PM Arathy RP <arathyrparathy at gmail.com>
>>>> wrote:
>>>>
>>>>> Hi,
>>>>> Yes, your guess is correct .
>>>>> For getting minimum value I use the command
>>>>> printMinMax (f_sub,0).
>>>>> And f_sub is the subset of variable f . Variable f defines MSLP.
>>>>> I think if possible can you give a look at the whole code for
>>>>> convinence.
>>>>> I hereby attach the code .
>>>>>
>>>>>
>>>>>
>>>>> On Thu, Jun 4, 2020, 7:21 PM Barry Lynn <barry.h.lynn at gmail.com>
>>>>> wrote:
>>>>>
>>>>>> Hi:
>>>>>>
>>>>>> That doesn't look light the minimum.  What does the 32 indicate?
>>>>>>
>>>>>> I don't see your whole code in the email chain, although I thought it
>>>>>> was present.
>>>>>>
>>>>>> the variable f is the data MSL... at time 32 is my guess.
>>>>>>
>>>>>> You can do printVarSummary(f), to see the indices.
>>>>>>
>>>>>> I am not sure what f_sub is.  Is it supposed to be a subset of f?
>>>>>>
>>>>>> Can you just paste in the part where you think you are calculating
>>>>>> the minimum pressure, please.
>>>>>>
>>>>>> Barry
>>>>>>
>>>>>> Barry
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Thu, Jun 4, 2020 at 3:18 PM Arathy RP <arathyrparathy at gmail.com>
>>>>>> wrote:
>>>>>>
>>>>>>> Hi,
>>>>>>> f=data->MSL_GDS0_SFC(32,:,:)
>>>>>>> And this part gives the minimum value of mean sea level pressure
>>>>>>> printMinMax(f_sub,0)
>>>>>>>
>>>>>>> On Thu, Jun 4, 2020, 1:44 PM Barry Lynn <barry.h.lynn at gmail.com>
>>>>>>> wrote:
>>>>>>>
>>>>>>>> Which part gives you the mslp?
>>>>>>>>
>>>>>>>> On Thu, 4 Jun 2020 at 10:16 Arathy RP <arathyrparathy at gmail.com>
>>>>>>>> wrote:
>>>>>>>>
>>>>>>>>> Hi,
>>>>>>>>> Actually there is no error showing while running ncl code so i am
>>>>>>>>> not able to find which part of code is not working.
>>>>>>>>>
>>>>>>>>> On Thu, Jun 4, 2020, 12:36 PM Barry Lynn <barry.h.lynn at gmail.com>
>>>>>>>>> wrote:
>>>>>>>>>
>>>>>>>>>> Thank you for clarifying.
>>>>>>>>>>
>>>>>>>>>> I’d forgotten that strange way of referring to the level of the
>>>>>>>>>> sea.
>>>>>>>>>>
>>>>>>>>>> Send me the part of the code you think is not working and I
>>>>>>>>>> should be able to help in a few hours.
>>>>>>>>>>
>>>>>>>>>> Barry
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> On Thu, 4 Jun 2020 at 9:55 Arathy RP <arathyrparathy at gmail.com>
>>>>>>>>>> wrote:
>>>>>>>>>>
>>>>>>>>>>> Hi,
>>>>>>>>>>> Actually mean sea level pressure doesn't make a sense of average
>>>>>>>>>>> of pressure , it simply meant the pressure of mean sea level and not
>>>>>>>>>>> related to averaging.
>>>>>>>>>>>
>>>>>>>>>>> On Thu, Jun 4, 2020, 12:04 PM Barry Lynn <barry.h.lynn at gmail.com>
>>>>>>>>>>> wrote:
>>>>>>>>>>>
>>>>>>>>>>>> Hi:
>>>>>>>>>>>>
>>>>>>>>>>>> You need to reply to all, or they will get lost.
>>>>>>>>>>>>
>>>>>>>>>>>> What do you imply by "mean sea level pressure?"  Do you imply
>>>>>>>>>>>> that the pressure is averaged?
>>>>>>>>>>>>
>>>>>>>>>>>> It is not hard to find the minimum in an data field, so please
>>>>>>>>>>>> just clarify and I will try to help you.
>>>>>>>>>>>>
>>>>>>>>>>>> It is hard for me to correct other people's code, but I can
>>>>>>>>>>>> send you code that should work to identify the minimum sea level pressure,
>>>>>>>>>>>> or at least help you to adapt your own.
>>>>>>>>>>>>
>>>>>>>>>>>> Barry
>>>>>>>>>>>>
>>>>>>>>>>>> On Thu, Jun 4, 2020 at 9:20 AM Arathy RP <
>>>>>>>>>>>> arathyrparathy at gmail.com> wrote:
>>>>>>>>>>>>
>>>>>>>>>>>>> Hi,
>>>>>>>>>>>>> Actually i want to get the minimum value for mean sea level
>>>>>>>>>>>>> pressure and I didn't understand the purpose for defining area .
>>>>>>>>>>>>> Can you please show an example.
>>>>>>>>>>>>>
>>>>>>>>>>>>> On Thu, Jun 4, 2020, 12:45 AM Barry Lynn <
>>>>>>>>>>>>> barry.h.lynn at gmail.com> wrote:
>>>>>>>>>>>>>
>>>>>>>>>>>>>> Hi:
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> If you are plotting mean sea level pressure, you need to
>>>>>>>>>>>>>> define over what area you calculate the mean. Otherwise, your mean will
>>>>>>>>>>>>>> encompass an area much larger than the storm's center.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> For instance, you could calculate the mean in areas where the
>>>>>>>>>>>>>> wind speed is greater than some value, using the "where" statement.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> Do you do that?
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> Barry
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> On Wed, Jun 3, 2020 at 9:50 PM Arathy RP <
>>>>>>>>>>>>>> arathyrparathy at gmail.com> wrote:
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Hi,
>>>>>>>>>>>>>>> Yes, I will do that.
>>>>>>>>>>>>>>> Actually I am plotting mean sea level pressure of very
>>>>>>>>>>>>>>> severe cyclonic storm Phailin.And I want to get the minimum mean sea level
>>>>>>>>>>>>>>> pressure as 994.29Pa only. As the cyclone belongs to category 5 storm the
>>>>>>>>>>>>>>> pressure level should go beyond 960Pa so that intensified contour plot of
>>>>>>>>>>>>>>> Phailin i will get. And the code is written by me by refering ncl sites.
>>>>>>>>>>>>>>> I hereby attach the variable details and minimum pressure
>>>>>>>>>>>>>>> showing when plotted.
>>>>>>>>>>>>>>> Thanking you
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> On Wed, Jun 3, 2020 at 8:31 PM Barry Lynn <
>>>>>>>>>>>>>>> barry.h.lynn at gmail.com> wrote:
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> Hi:
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> Can you show us what you are getting and what pressure you
>>>>>>>>>>>>>>>> print out as the center pressure.  This would help identify the problem.
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> Also, where did you get the code to make the surface
>>>>>>>>>>>>>>>> pressure maps/tracking? Can you define what you mean by minimum contour
>>>>>>>>>>>>>>>> plot.
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> Barry
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> On Wed, Jun 3, 2020 at 4:27 PM Arathy RP via ncl-talk <
>>>>>>>>>>>>>>>> ncl-talk at ucar.edu> wrote:
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>> Hi,
>>>>>>>>>>>>>>>>> I am arz student of MSc finally year . As a part of my
>>>>>>>>>>>>>>>>> project work , i am working with cyclone contour plotting.I am dealing with
>>>>>>>>>>>>>>>>> cyclone phailin and i want to get minimum value contour plot for mean sea
>>>>>>>>>>>>>>>>> level pressure of cyclone.Actually there is no error showing even though i
>>>>>>>>>>>>>>>>> am getting a wrong value. I can't find what wrong with this .can you please
>>>>>>>>>>>>>>>>> help me to clarify it.
>>>>>>>>>>>>>>>>> I am dealing with an intensified cyclone plot but not
>>>>>>>>>>>>>>>>> getting a result as expected. Please help me.
>>>>>>>>>>>>>>>>> I hereby attaching the data and ncl script used.
>>>>>>>>>>>>>>>>> _______________________________________________
>>>>>>>>>>>>>>>>> ncl-talk mailing list
>>>>>>>>>>>>>>>>> ncl-talk at ucar.edu
>>>>>>>>>>>>>>>>> List instructions, subscriber options, unsubscribe:
>>>>>>>>>>>>>>>>> http://mailman.ucar.edu/mailman/listinfo/ncl-talk
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> --
>>>>>>>>>>>>>>>> Barry H. Lynn, Ph.D
>>>>>>>>>>>>>>>> Senior Associate Scientist, Lecturer,
>>>>>>>>>>>>>>>> The Institute of the Earth Science,
>>>>>>>>>>>>>>>> The Hebrew University of Jerusalem,
>>>>>>>>>>>>>>>> Givat Ram, Jerusalem 91904, Israel
>>>>>>>>>>>>>>>> Tel: 972 547 231 170
>>>>>>>>>>>>>>>> Fax: (972)-25662581
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> C.E.O, Weather It Is, LTD
>>>>>>>>>>>>>>>> Weather and Climate Focus
>>>>>>>>>>>>>>>> http://weather-it-is.com
>>>>>>>>>>>>>>>> Jerusalem, Israel
>>>>>>>>>>>>>>>> Local: 02 930 9525
>>>>>>>>>>>>>>>> Cell: 054 7 231 170
>>>>>>>>>>>>>>>> Int-IS: x972 2 930 9525
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> --
>>>>>>>>>>>>>> Barry H. Lynn, Ph.D
>>>>>>>>>>>>>> Senior Associate Scientist, Lecturer,
>>>>>>>>>>>>>> The Institute of the Earth Science,
>>>>>>>>>>>>>> The Hebrew University of Jerusalem,
>>>>>>>>>>>>>> Givat Ram, Jerusalem 91904, Israel
>>>>>>>>>>>>>> Tel: 972 547 231 170
>>>>>>>>>>>>>> Fax: (972)-25662581
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> C.E.O, Weather It Is, LTD
>>>>>>>>>>>>>> Weather and Climate Focus
>>>>>>>>>>>>>> http://weather-it-is.com
>>>>>>>>>>>>>> Jerusalem, Israel
>>>>>>>>>>>>>> Local: 02 930 9525
>>>>>>>>>>>>>> Cell: 054 7 231 170
>>>>>>>>>>>>>> Int-IS: x972 2 930 9525
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>> --
>>>>>>>>>>>> Barry H. Lynn, Ph.D
>>>>>>>>>>>> Senior Associate Scientist, Lecturer,
>>>>>>>>>>>> The Institute of the Earth Science,
>>>>>>>>>>>> The Hebrew University of Jerusalem,
>>>>>>>>>>>> Givat Ram, Jerusalem 91904, Israel
>>>>>>>>>>>> Tel: 972 547 231 170
>>>>>>>>>>>> Fax: (972)-25662581
>>>>>>>>>>>>
>>>>>>>>>>>> C.E.O, Weather It Is, LTD
>>>>>>>>>>>> Weather and Climate Focus
>>>>>>>>>>>> http://weather-it-is.com
>>>>>>>>>>>> Jerusalem, Israel
>>>>>>>>>>>> Local: 02 930 9525
>>>>>>>>>>>> Cell: 054 7 231 170
>>>>>>>>>>>> Int-IS: x972 2 930 9525
>>>>>>>>>>>>
>>>>>>>>>>>> --
>>>>>>>>>> Barry H. Lynn, Ph.D
>>>>>>>>>> Senior Associate Scientist, Lecturer,
>>>>>>>>>> The Institute of the Earth Science,
>>>>>>>>>> The Hebrew University of Jerusalem,
>>>>>>>>>> Givat Ram, Jerusalem 91904, Israel
>>>>>>>>>> Tel: 972 547 231 170
>>>>>>>>>> Fax: (972)-25662581
>>>>>>>>>>
>>>>>>>>>> C.E.O, Weather It Is, LTD
>>>>>>>>>> Weather and Climate Focus
>>>>>>>>>> http://weather-it-is.com
>>>>>>>>>> Jerusalem, Israel
>>>>>>>>>> Local: 02 930 9525
>>>>>>>>>> Cell: 054 7 231 170
>>>>>>>>>> Int-IS: x972 2 930 9525
>>>>>>>>>>
>>>>>>>>>> --
>>>>>>>> Barry H. Lynn, Ph.D
>>>>>>>> Senior Associate Scientist, Lecturer,
>>>>>>>> The Institute of the Earth Science,
>>>>>>>> The Hebrew University of Jerusalem,
>>>>>>>> Givat Ram, Jerusalem 91904, Israel
>>>>>>>> Tel: 972 547 231 170
>>>>>>>> Fax: (972)-25662581
>>>>>>>>
>>>>>>>> C.E.O, Weather It Is, LTD
>>>>>>>> Weather and Climate Focus
>>>>>>>> http://weather-it-is.com
>>>>>>>> Jerusalem, Israel
>>>>>>>> Local: 02 930 9525
>>>>>>>> Cell: 054 7 231 170
>>>>>>>> Int-IS: x972 2 930 9525
>>>>>>>>
>>>>>>>>
>>>>>>
>>>>>> --
>>>>>> Barry H. Lynn, Ph.D
>>>>>> Senior Associate Scientist, Lecturer,
>>>>>> The Institute of the Earth Science,
>>>>>> The Hebrew University of Jerusalem,
>>>>>> Givat Ram, Jerusalem 91904, Israel
>>>>>> Tel: 972 547 231 170
>>>>>> Fax: (972)-25662581
>>>>>>
>>>>>> C.E.O, Weather It Is, LTD
>>>>>> Weather and Climate Focus
>>>>>> http://weather-it-is.com
>>>>>> Jerusalem, Israel
>>>>>> Local: 02 930 9525
>>>>>> Cell: 054 7 231 170
>>>>>> Int-IS: x972 2 930 9525
>>>>>>
>>>>>>
>>>>
>>>> --
>>>> Barry H. Lynn, Ph.D
>>>> Senior Associate Scientist, Lecturer,
>>>> The Institute of the Earth Science,
>>>> The Hebrew University of Jerusalem,
>>>> Givat Ram, Jerusalem 91904, Israel
>>>> Tel: 972 547 231 170
>>>> Fax: (972)-25662581
>>>>
>>>> C.E.O, Weather It Is, LTD
>>>> Weather and Climate Focus
>>>> http://weather-it-is.com
>>>> Jerusalem, Israel
>>>> Local: 02 930 9525
>>>> Cell: 054 7 231 170
>>>> Int-IS: x972 2 930 9525
>>>>
>>>>

-- 
Barry H. Lynn, Ph.D
Senior Associate Scientist, Lecturer,
The Institute of the Earth Science,
The Hebrew University of Jerusalem,
Givat Ram, Jerusalem 91904, Israel
Tel: 972 547 231 170
Fax: (972)-25662581

C.E.O, Weather It Is, LTD
Weather and Climate Focus
http://weather-it-is.com
Jerusalem, Israel
Local: 02 930 9525
Cell: 054 7 231 170
Int-IS: x972 2 930 9525
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