[ncl-talk] Time Vs Lat/Lon

Kunal Bali kunal.bali9 at gmail.com
Thu Nov 1 00:37:42 MDT 2018 

I tried this but not working

    arr    = a->BCSMASS
    lat    = a->lat
    lon    = a->lon

    printVarSummary(arr)
    timeT = cd_calendar(arr&time,-4)   [==> *getting a warning*:cd_calendar:
Unknown option, defaulting to 0.]
    time = timeT(:,3)

    ;arr_min = dim_min( arr(lat|:, lon|:, time|:) )
    ;printVarSummary(arr_min)
    ;printMinMax(arr_min,0)

    ;arr_max = dim_max( arr(lat|:, lon|:, time|:) )
    ;printVarSummary(arr_max)
    ;printMinMax(arr_max,0)

    ;time_min = arr_min    ; arr_min contains the indices that were the
minimum at each lat/lon point
    ;time_max = arr_max
    ;printVarSummary(time_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

---
Kunal Bali







On Thu, Nov 1, 2018 at 3:05 AM Adam Phillips <asphilli at ucar.edu> wrote:

> Hi Kunal,
> Note that I recommended using dim_minind/dim_maxind, and not
> minind/maxind. Looking at the file you attached, you would pass your
> BCSMASS array into those two functions, and operate on the time (0)
> dimension. As previously stated, that will return a 2D array dimensioned
> lat x lon containing the desired indices. Then you would apply the double
> do loop coding I sent to form arrays of the times themselves.  Again, the
> time array in my example coding needs to be set to something that is easily
> plotted, say the Hour. You can set up an hour array for your data like this:
> a = addfile("hourmean.nc","r")
> arr = a->BCSMASS
> timeT = cd_calendar(arr&time,-4)
> time = timeT(:,3)
>
> Adam
>
> On Tue, Oct 30, 2018 at 12:02 PM Kunal Bali <kunal.bali9 at gmail.com> wrote:
>
>> 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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>
>
> --
> 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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