[ncl-talk] stat_despersion

[ali mughal]

Sorry a correction to the above email is that all values in grid_stats,
tenthP and nintythP are 0.

On Thu, Jul 1, 2021 at 11:49 AM ali mughal <mughalali655 at gmail.com> wrote:

> Dear All
>
> Here is how I have modified the code according to your suggestions.
> However, I am getting all values in the output of grid_stats.and when I try
> plotting the tenth percentile I also have a zero value.  I will be
> extremely grateful for your support.
>
>
> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"
> a=addfile("wrfout","r")
> ta_mean_BEM=a->TA_MEAN
> ta=ta_mean_BEM(24:719,0,:,:)
> ta=ta-273.16
> nlat1=ta(0,:,0)
> mlon1=ta(0,0,:)
>
>
>  nlStrt=0
>  nlLast=129
>  mlStrt=0
>  mlLast=210
>  nlat=dimsizes(nlat1)
>  mlon=dimsizes(mlon1)
>
>  grid_stats = new ((/nlat,mlon,30/), typeof(ta), getFillValue(ta))
>     do nl=nlStrt,nlStrt-1
>       do ml=mlStrt,mlStrt-1
>
>          grid_stats(nl-nlStrt,ml-mlStrt,:) = stat_dispersion( ta(:,nl,ml),
> opt)
>
>       end do
>    end do
>
> tenthP=grid_stats(:,:,3)
>
> nintythP=grid_stats(:,:,13)
>
>
> type = "png"
> wks = gsn_open_wks(type,"abc")
> res =True
> opts = res
> opts at cnFillOn = True
> opts at cnConstFEnableFill           = True
> opts at cnConstFLabelBackgroundColor = "transparent"
>
>
> pltres = True
> pltres at NoTitles = True
> pltres at gsnMaximize = True
> pltres at FramePlot = False
> pltres at PanelPlot = True
> mpres = True
> mpres at mpOutlineBoundarySets    ="NoBoundaries"
> contour_lh = wrf_contour(a,wks,tenthP,opts)
> delete(opts)
>
> plot = wrf_map_overlays(a,wks,(/contour_lh/),pltres,mpres)
> draw(plot)
> frame(wks)
>
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> On Wed, Jun 30, 2021 at 10:24 PM Dave Allured - NOAA Affiliate <
> dave.allured at noaa.gov> wrote:
>
>> Also, stat_dispersion returns an array of 30 values each time, not a
>> single value.  See function documentation.  So you need to add an extra
>> dimension in the loop calculation, like this:
>>
>>     grid_stats = new ((/ nlat, mlon, 30 /), typeof(rf), getFillValue(rf))
>>
>>     do ...
>>        do ...
>>          grid_stats(nl-nlStrt,ml-mlStrt,:) = stat_dispersion(
>> rf(:,nl,ml), opt)
>>       end do
>>     end do
>>
>> When the loop is complete, the 10th percentile values will be in
>> grid_stats(:,:,3), which is a 2-D grid that you can plot.  The 90th
>> percentile values will be in grid_stats(:,:,13).  Again, refer to the
>> function documentation for the correct index values to access the desired
>> statistics.
>>
>>
>> On Wed, Jun 30, 2021 at 5:13 AM Buzan, Jonathan <jbuzan at purdue.edu>
>> wrote:
>>
>>> NCL counts from 0 to n-1, not from 1 to n. So your loop vars need to
>>> account for that.
>>>
>>> Cheers,
>>> -Jonathan
>>>
>>> On Jun 30, 2021, at 1:10 PM, ali mughal via ncl-talk <
>>> ncl-talk at mailman.ucar.edu> wrote:
>>>
>>> Dear community
>>> Thank you very much for your helpful comments.
>>> As an initial test, I was trying to obtain statistics at all grid points
>>> before plotting them. I used the following code
>>> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"
>>> a=addfile("wrfout","r")
>>> ta_mean_BEM=a->TA_MEAN
>>> ta=ta_mean_BEM(24:719,0,:,:)
>>> rf=ta-273.16
>>> nlat1=rf(0,:,0)
>>> printVarSummary(nlat)
>>> mlon1=rf(0,0,:)
>>> printVarSummary(mlon)
>>> printVarSummary(rf)
>>> opt=False
>>>
>>>      nlStrt=0
>>>      nlLast=129
>>>      mlStrt=0
>>>      mlLast=210
>>>      nlat=dimsizes(nlat1)
>>>      mlon=dimsizes(mlon1)
>>>
>>>     grid_stats = new ((/nlat(0),mlon(0)/), typeof(rf), getFillValue(rf))
>>>     printVarSummary(grid_stats)
>>>     do nl=0,nlLast
>>>       do ml=0,mlLast
>>>
>>>          grid_stats(nl-nlStrt,ml-mlStrt) = stat_dispersion( rf(:,nl,ml),
>>> opt)
>>>
>>>       end do
>>>    end do
>>>
>>>    copy_VarCoords(rf(:,nlStrt:nlLast,mlStrt:mlLast), grid_stats)
>>>    grid_stats at long_name = "stat_dispersion at individual grid points"
>>>    printVarSummary(grid_stats)
>>>
>>> But I obtain the following output from my print statements and the errors
>>>
>>> Variable: rf
>>> Type: float
>>> Total Size: 75418560 bytes
>>>             18854640 values
>>> Number of Dimensions: 3
>>> Dimensions and sizes:   [696] x [129] x [210]
>>> Coordinates:
>>>
>>> Variable: grid_stats
>>> Type: float
>>> Total Size: 108360 bytes
>>>             27090 values
>>> Number of Dimensions: 2
>>> Dimensions and sizes:   [129] x [210]
>>> Coordinates:
>>> fatal:VarVarWrite: Number of dimensions on left hand side does not match
>>> right hand side
>>> fatal:["Execute.c":8578]:Execute: Error occurred at or near line 46 in
>>> file var_Test.ncl
>>>
>>> fatal:Subscript out of range, error in subscript #1
>>> fatal:An error occurred reading rf
>>> fatal:["Execute.c":8578]:Execute: Error occurred at or near line 51 in
>>> file var_Test.ncl
>>>
>>> Variable: grid_stats
>>> Type: float
>>> Total Size: 108360 bytes
>>>             27090 values
>>> Number of Dimensions: 2
>>> Dimensions and sizes:   [129] x [210]
>>> Coordinates:
>>> Number Of Attributes: 1
>>>   long_name :   stat_dispersion at individual grid points
>>>
>>>
>>> On Wed, Jun 30, 2021 at 12:01 AM Dave Allured - NOAA Affiliate <
>>> dave.allured at noaa.gov> wrote:
>>>
>>>> Ali, you do not need to make new code to find the 10th and 90th
>>>> percentile values.  Just use stat_dispersion directly, and take only the
>>>> output values that you need.  The function is designed to be used in this
>>>> way.  There is no significant performance impact from ignoring all the
>>>> other result values.
>>>>
>>>> You can easily make a spatial map of 10th or 90th percentile values.
>>>> Just call stat_dispersion inside a double loop over X and Y dimensions.
>>>>
>>>>
>>>> On Tue, Jun 29, 2021 at 9:23 AM Buzan, Jonathan via ncl-talk <
>>>> ncl-talk at mailman.ucar.edu> wrote:
>>>>
>>>>> Hello,
>>>>>
>>>>> I’ve used that function a bunch. If you only want 10th and 90th
>>>>> percentile, you’ll want to use:
>>>>>
>>>>> qsort
>>>>> Which will sort your data within a single grid cell from lowest to
>>>>> highest.
>>>>>
>>>>> And then grab the specific lines of code for 10th and 90th percentiles
>>>>> from the stat_dispersion function in:
>>>>> $NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl
>>>>>
>>>>> If you look at the function, you’ll see that it uses qsort, then goes
>>>>> step by step through calculating all the different applications.
>>>>>
>>>>> Cheers,
>>>>> -Jonathan
>>>>>
>>>>> On Jun 29, 2021, at 5:14 PM, ali mughal via ncl-talk <
>>>>> ncl-talk at mailman.ucar.edu> wrote:
>>>>>
>>>>> Dear NCL community
>>>>>
>>>>> In the following ncl function
>>>>>
>>>>>
>>>>> http://www.ncl.ucar.edu/Document/Functions/Contributed/stat_dispersion.shtml
>>>>>
>>>>> Is it possible to use 10th and 90th percentile values only ?
>>>>>
>>>>> Also can these values be used to develop a spatial map?
>>>>>
>>>>> For example if I want to find the 10th and  90th percentile of air
>>>>> temperature within the urban grid cells only.
>>>>>
>>>>> Can anyone share an example script or point me to any web
>>>>> resource will be appreciated.
>>>>>
>>>>> Thanks in advance
>>>>>
>>>>>
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