[ncl-talk] Coefficient_of Divergence
Kunal Bali
kunal.bali9 at gmail.com
Thu Nov 9 23:34:40 MST 2017
Sorry for the inconvenience regarding previous mail. please ignore that.
I have figured it out the problem.
Thanks for all the suggestions Dennis Sir.
regards
Kunal Bali
On Fri, Nov 10, 2017 at 11:56 AM, Kunal Bali <kunal.bali9 at gmail.com> wrote:
> Dear Dennis Sir,
> thanks for the suggestion.
> it is working with few time steps, but not for say 442-time steps.
>
> I tried your suggestion, now it is not able to calculate the CoD.
>
> I simply used
>
> ;-----calculation of coefficient of divergence
> DATA_SINGLE_3D = conform(data_subset, data_single, 0)
> x1 = (DATA_SINGLE_3D - data_subset)
> x2 = (DATA_SINGLE_3D + data_subset)
> * CoD1 = (x1/ where(x2.ne.0, x2, x2 at _FillValue))^2 *
> printVarSummary(CoD1)
> printMinMax(CoD1, 0)
> print("---")
>
> *CoD2 = dim_avg_n_Wrap(CoD1, 0) * ; (nlat,mlon)
> CoD2 at long_name = "Coef of Divergence"
> printVarSummary(CoD2)
> printMinMax(CoD2,0)
>
> CoD2_avg = avg(CoD2) ; small area; no need to
> weight
> ; for plotting only
>
> *CoD_final = sqrt(CoD2)*
> printVarSummary(CoD3)
> printMinMax(CoD3,0)
>
> CoD3 at lat2d = lat(ilt1:ilt2,iln1:iln2) ; use := to force
> reassignment of lat2d
> CoD3 at lon2d = lon(ilt1:ilt2,iln1:iln2) ; ditto
>
> ; res at gsnRightString = "avg(CoD2)="+sprintf("%5.3f", CoD2_avg)
> *plot = gsn_csm_contour_map(wks,CoD_final,res)*
> the errors are
>
> *Variable: CoD1*
> Type: float
> Total Size: 1736176 bytes
> 434044 values
> Number of Dimensions: 3
> Dimensions and sizes: [442] x [1] x [982]
> Coordinates:
> Number Of Attributes: 1
> _FillValue : -28672
> (0) min=0 max=1
> (0) ---
>
> *Variable: CoD2*
> Type: float
> Total Size: 3928 bytes
> 982 values
> Number of Dimensions: 2
> Dimensions and sizes: [1] x [982]
> Coordinates:
> Number Of Attributes: 3
> long_name : Coef of Divergence
> _FillValue : -28672
> average_op_ncl : dim_avg_n function was applied
> (0) Coef of Divergence : min=0 max=1
>
> *Variable: CoD3*
> Type: float
> Total Size: 3928 bytes
> 982 values
> Number of Dimensions: 2
> Dimensions and sizes: [1] x [982]
> Coordinates:
> Number Of Attributes: 1
> _FillValue : -28672
> (0) min=0 max=1
> fatal:ScalarFieldInitialize: Insufficient number of elements in sfDataArray
> fatal:Unable to initialize layer-Can't Create
> fatal:Unable to access object with id:-4
> fatal:PID #-4 can't be found in NhlSetValues
> fatal:Unable to access object with id:-4
> warning:Unable to add DataItem "(null)" to DataList "cnScalarFieldData"
> fatal:CompileDataList:DataList has no valid members
>
>
> regards
> Kunal Bali
>
>
>
>
>
>
> On Fri, Nov 10, 2017 at 3:20 AM, Dennis Shea <shea at ucar.edu> wrote:
>
>> [1] I do not have the file:
>> maiactaotE.h00v02.20010040635-20011550640.nc
>>
>>
>> [2] where: See the 'Caveat' in the documentation
>> https://www.ncl.ucar.edu/Document/Functions/Built-in/where.shtml
>>
>>
>>
>> *CoD = 1. / where(x2.ne.0, x1/x2, x2 at _FillValue) ; it can be
>> divisible by 0 *
>> should be
>>
>> *CoD = (x1 / where(x2.ne.0, x2, x2 at _FillValue))^2 *
>>
>>
>> [3] I used a file with only a few time steps. See attached
>>
>>
>>
>> On Wed, Nov 8, 2017 at 11:05 PM, Kunal Bali <kunal.bali9 at gmail.com>
>> wrote:
>>
>>>
>>> when I try the attached script (plot1.ncl) for large time steps say 442
>>> then
>>> it shows an error
>>>
>>>
>>>
>>> *fatal:divide: Division by 0, Can't continuefatal:Div: operator failed,
>>> can't continuefatal:["Execute.c":8640]:Execute: Error occurred at or near
>>> line 120 in file plot.ncl*
>>>
>>> *120 line is *
>>> CoD1 = ((DATA_SINGLE_3D - data_subset)/(DATA_SINGLE_3D + data_subset))^2
>>>
>>> So I separated this line to
>>> x1 = (DATA_SINGLE_3D - data_subset)
>>> x2 = (DATA_SINGLE_3D + data_subset)
>>>
>>> and then tried
>>>
>>>
>>> *CoD = 1. / where(x2.ne.0, x1/x2, x2 at _FillValue) ; it can be
>>> divisible by 0 CoD1 = (CoD)^2*
>>> printVarSummary(CoD1)
>>> printMinMax(CoD1, 0)
>>>
>>>
>>> But, still showing the same error
>>>
>>>
>>>
>>> *fatal:divide: Division by 0, Can't continuefatal:Div: operator failed,
>>> can't continuefatal:["Execute.c":8640]:Execute: Error occurred at or near
>>> line 120 in file plot.ncl*
>>>
>>>
>>> regards
>>> Kunal Bali
>>>
>>>
>>>
>>>
>>>
>>>
>>> On Wed, Nov 8, 2017 at 10:56 AM, Kunal Bali <kunal.bali9 at gmail.com>
>>> wrote:
>>>
>>>> I followed your instruction, But now CoD1 and CoD2 values are showing
>>>> the same values, which is incorrect? and because of this values of the
>>>> square root of CoD2 is not correct.
>>>>
>>>>
>>>> ;-----calculation of coefficient of divergence
>>>> CoD1 = ((DATA_SINGLE_3D - data_subset)/(DATA_SINGLE_3D+
>>>> data_subset))^2
>>>> printVarSummary(CoD1)
>>>> printMinMax(CoD1, 0)
>>>>
>>>> CoD1 at _FillValue = -28672
>>>> CoD2 = dim_avg_n_Wrap(CoD1, 0) ; (nlat,mlon)
>>>> printVarSummary(CoD2)
>>>> printMinMax(CoD2,0)
>>>>
>>>> CoD3 = sqrt(CoD2)
>>>> printVarSummary(CoD3)
>>>> printMinMax(CoD3, 0)
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> *Variable: CoD1Type: floatTotal Size: 7824960 bytes 1956240
>>>> valuesNumber of Dimensions: 3Dimensions and sizes: [3] x [660] x
>>>> [988]Coordinates: Number Of Attributes: 1 _FillValue : -28672(0)
>>>> min=0 max=0.961394Variable: CoD2Type: floatTotal Size: 2608320
>>>> bytes 652080 valuesNumber of Dimensions: 2Dimensions and
>>>> sizes: [660] x [988]Coordinates: Number Of Attributes: 2 _FillValue
>>>> : -28672 average_op_ncl : dim_avg_n function was applied(0)
>>>> min=0 max=0.961394Variable: CoD3Type: floatTotal Size: 2608320
>>>> bytes 652080 valuesNumber of Dimensions: 2Dimensions and
>>>> sizes: [660] x [988]Coordinates: Number Of Attributes: 1 _FillValue
>>>> : -28672(0) min=0 max=0.980507*
>>>>
>>>>
>>>>
>>>> regsrds
>>>> Kunal Bali
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> On Wed, Nov 8, 2017 at 3:55 AM, Dennis Shea <shea at ucar.edu> wrote:
>>>>
>>>>>
>>>>> *Variable: CoD1*
>>>>> *Dimensions and sizes: [3] x [660] x [988]*
>>>>> *(0) min=0 max=0.961394*
>>>>>
>>>>>
>>>>> step 2:
>>>>>
>>>>> CoD2 = sum(CoD1)/3 <=== No!
>>>>> printVarSummary(CoD2)
>>>>> printMinMax(CoD2, 0)
>>>>>
>>>>> https://www.ncl.ucar.edu/Document/Functions/Contributed/dim_
>>>>> avg_n_Wrap.shtml
>>>>>
>>>>> CoD2 = dim_avg_n_Wrap(CoD1, 0) ; (nlat,mlon)
>>>>> printVarSummary(CoD2)
>>>>> printMinMax(CoD2,0)
>>>>>
>>>>> ===
>>>>> If you still have large numbers, the find one grid point where a large
>>>>> number occurs, then print the values.
>>>>>
>>>>> print(CoD1(:,nn,mm)) ; print series where large numbers occur
>>>>> (indices: nn,mm)
>>>>>
>>>>> See documentation for
>>>>> https://www.ncl.ucar.edu/Document/Functions/Built-in/ind.shtml
>>>>> https://www.ncl.ucar.edu/Document/Functions/Built-in/ind_res
>>>>> olve.shtml
>>>>> See Examples 2 & 3
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> On Tue, Nov 7, 2017 at 1:32 PM, Kunal Bali <kunal.bali9 at gmail.com>
>>>>> wrote:
>>>>>
>>>>>> Thanks for suggesting this.
>>>>>>
>>>>>> Actually, I am trying to calculate the COD at each grid cell.
>>>>>>
>>>>>> So as you suggested
>>>>>>
>>>>>>
>>>>>> *DATA_SINGLE_3D = conform(data_subset, data_single, 0) ; it worked*
>>>>>>
>>>>>>
>>>>>>
>>>>>> *Variable: DATA_SINGLE_3DType: floatTotal Size: 7824960 bytes
>>>>>> 1956240 valuesNumber of Dimensions: 3Dimensions and sizes: [3] x [660]
>>>>>> x [988]Coordinates: Number Of Attributes: 1 _FillValue : -28672*
>>>>>> step 1:
>>>>>> CoD1 = ((DATA_SINGLE_3D - data_subset)/(DATA_SINGLE_3D+
>>>>>> data_subset))^2
>>>>>> printVarSummary(CoD1)
>>>>>> printMinMax(CoD1, 0)
>>>>>>
>>>>>> *Variable: CoD1*
>>>>>> *Type: float*
>>>>>> *Total Size: 7824960 bytes*
>>>>>> * 1956240 values*
>>>>>> *Number of Dimensions: 3*
>>>>>> *Dimensions and sizes: [3] x [660] x [988]*
>>>>>> *Coordinates: *
>>>>>> *Number Of Attributes: 1*
>>>>>> * _FillValue : -28672*
>>>>>> *(0) min=0 max=0.961394*
>>>>>>
>>>>>>
>>>>>> step 2:
>>>>>>
>>>>>> CoD2 = sum(CoD1)/3
>>>>>> printVarSummary(CoD2)
>>>>>> printMinMax(CoD2, 0)
>>>>>>
>>>>>> *Variable: CoD2*
>>>>>> *Type: float*
>>>>>> *Total Size: 4 bytes*
>>>>>> * 1 values*
>>>>>> *Number of Dimensions: 1*
>>>>>> *Dimensions and sizes: [1]*
>>>>>> *Coordinates: *
>>>>>> *(0) min=20691.8 max=20691.8 --------> values are very
>>>>>> high? and also it's not giving at each grid cell, because of that I can't
>>>>>> calculate the sqrt in the next step*
>>>>>>
>>>>>>
>>>>>> step 3:
>>>>>>
>>>>>> CoD3 = sqrt(CoD2)
>>>>>> printVarSummary(CoD3)
>>>>>> printMinMax(CoD2, 0)
>>>>>>
>>>>>>
>>>>>> The final values are coming very high. It should be less than 0.3 at
>>>>>> each grid cell.
>>>>>>
>>>>>> regards
>>>>>> Kunal Bali
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Wed, Nov 8, 2017 at 1:18 AM, Dennis Shea <shea at ucar.edu> wrote:
>>>>>>
>>>>>>> If you have a one-dimensional array (1D; eg: a 'time series') and a
>>>>>>> three-dimensional array (3D; eg: time series at multiple grid points), you
>>>>>>> *must* make the arrays 'conformant' for an array calculation
>>>>>>>
>>>>>>> You have:
>>>>>>> CoD1 = ((data_single(:) - data_subset(:,:,:))/(data_single(:) +
>>>>>>> data_subset(:,:,:)))^2
>>>>>>>
>>>>>>> You did not include a 'printVarSummary' of these variables. Assuming
>>>>>>> data_single(ntim) and data_subset(ntim,nlat,mlon) then you must replicate
>>>>>>> (aka, propogate) the 1D array to the 3D array size. In NCL, this is called
>>>>>>> 'array conformance' . Please see and carefully read:
>>>>>>>
>>>>>>> https://www.ncl.ucar.edu/Document/Functions/Built-in/conform.shtml
>>>>>>> https://www.ncl.ucar.edu/Document/Functions/Built-in/conform
>>>>>>> _dims.shtml
>>>>>>>
>>>>>>> ---
>>>>>>> DATA_SINGLE_3D = conform(data_subset, data_single, 0) ;
>>>>>>> (ntim,nlat,mlon)
>>>>>>> printVarSummary(DATA_SINGLE_3D) ; Look at data
>>>>>>>
>>>>>>> Do *not* use (:,:,:) in a computation... this is inefficient.
>>>>>>>
>>>>>>> CoD1 = ((DATA_SINGLE_3D - data_subset)/(DATA_SINGLE_3D+
>>>>>>> data_subset))^2
>>>>>>> printVarSummary(CoD1)
>>>>>>> printMinMax(CoD1, 0)
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> On Tue, Nov 7, 2017 at 11:15 AM, Kunal Bali <kunal.bali9 at gmail.com>
>>>>>>> wrote:
>>>>>>>
>>>>>>>> Dear NCL user
>>>>>>>>
>>>>>>>> Suppose, I have 2 datasets
>>>>>>>> e.g.
>>>>>>>>
>>>>>>>> data1 = of single point lat & lon (e.g 28N, 72E) with time steps
>>>>>>>> 365 (having filling values)
>>>>>>>> data2 = of grid box (24-32N, 68-76E) with time steps 365 (having
>>>>>>>> filling values)
>>>>>>>>
>>>>>>>> Now I want to calculate the CoD from one single point to 400km
>>>>>>>> grid box area and then lot the spatial map of the calculated product.
>>>>>>>>
>>>>>>>> Formula for CoD is GIVEN BELOW
>>>>>>>>
>>>>>>>>
>>>>>>>> So I calculated in NCL as
>>>>>>>>
>>>>>>>> CoD1 = ((data1 - data2)/(data1 + data2))^2
>>>>>>>> CoD_final = (sqrt(sum(CoD1)))/3
>>>>>>>>
>>>>>>>> please let me know is it the right way to do?
>>>>>>>>
>>>>>>>> I tried to plot the final product CoD_final with the attached
>>>>>>>> script, but error comes as
>>>>>>>>
>>>>>>>> fatal:Minus: Number of dimensions do not match, can't continue
>>>>>>>> fatal:["Execute.c":8578]:Execute: Error occurred at or near line
>>>>>>>> 116 in file plot.ncl
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> regards
>>>>>>>> Kunal Bali
>>>>>>>>
>>>>>>>>
>>>>>>>> _______________________________________________
>>>>>>>> ncl-talk mailing list
>>>>>>>> ncl-talk at ucar.edu
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>>>>>>>>
>>>>>>>
>>>>>>
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>>>>>
>>>>
>>>
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