[ncl-talk] Time Vs Lat/Lon

[Kunal Bali]

Thanks for this informations.

I tried to get min mad max by using the link which you mentioned, but the
error comes with fatal:Argument type mismatch on argument (0) of (maxind)
can not coerce

I also tried the code given below but facing the same error here.
(version-NCL 6.4.0)

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 maxind
  inds = *ind_resolve*
<https://www.ncl.ucar.edu/Document/Functions/Built-in/ind_resolve.shtml>(*maxind*
(x1d), dims)    ; convert 1D array back to 2D
  ilat = inds(0,0)        ; select the latitude index where the X
array is at its' maximum
  ilon = inds(0,1)        ; select the longitude index where the X
array is at its' maximum
  lat_max = X&lat(ilat)   ; insert the latitude index into the lat
coordinate variable
  lon_max = X&lon(ilon)   ; insert the longitude index into the lon
coordinate variable
  *print* <https://www.ncl.ucar.edu/Document/Functions/Built-in/print.shtml>("Maximum
value located at "+lat_max+", "+lon_max)

I also attached one sample file, in case if you need it.


---
Kunal Bali






On Tue, Oct 30, 2018 at 2:47 AM Adam Phillips <asphilli at ucar.edu> wrote:

> Hi Kunal,
> If I understand correctly what you are after, you'd like to plot the time
> (at each grid point) where the maximum (or minimum) value occurs.
> This will likely take some trial and error on your part. Here's what I
> think you need to do:
> 1) Use dim_minind and dim_maxind to isolate the index where the grid point
> value is at its min/max.
> https://www.ncl.ucar.edu/Document/Functions/Contributed/dim_maxind.shtml
> https://www.ncl.ucar.edu/Document/Functions/Contributed/dim_minind.shtml
>
> This will result in a 2-D array (dimensioned lat x lon) containing the
> minimum indices, and the same type of array containing the maximum indices.
>
> 2)  There might be a more elegant way to map the indexes onto the correct
> times, but the following double do loop over the lat/lon dimensions will
> work:
>
> ; time is an array of your times
> time_min = arr_min    ; arr_min contains the indices that were the minimum
> at each lat/lon point
> time_max = arr_max
> do gg = 0,dimsizes(arr_min&lat)-1
>      do hh = 0,dimsizes(arr_min&lon)-1
>           time_min(gg,hh) = time(arr_min(gg,hh))
>           time_max(gg,hh) = time(arr_max(gg,hh))
>      end do
> end do
>
> You will want to make sure that your time array is in a format that is
> conducive to being plotted. (18:30 doesn't work for instance, but 1830
> would.)
> I think that's it. Try starting with the above suggestions and see if you
> can get things to work. If you have further questions about this subject
> please reply to the ncl-talk email list.
> Adam
>
>
>
> On Mon, Oct 29, 2018 at 6:57 AM Kunal Bali <kunal.bali9 at gmail.com> wrote:
>
>> Dear NCL users,
>>
>> I have one file (2000-2017) with time, latitude, longitude and  variable.
>> The time is given in hours(00:30 to 18:30). I need to plot a spatial map of
>> hours values at each grid cells, the contour map of hours values should
>> correspond to the variable values. So that I can see which hour has high
>> and low-value on the map. Some examples are given for time vs latitude and
>> time vs longitude, I don't need that.  I need to plot time vs latitude
>> longitude.
>>
>> I hope you got my point.
>> Any information on that?
>>
>> Thank You
>> ---
>> Kunal Bali
>>
>>
>>
>>
>>
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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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