Re: help with Replacing missing value in an array with zeros

Hi Erik,

The output from
min_r = min(r)
print(min_r)

shows you that you data has a minimum value of -9999. I wonder whether
your _FillValue is set incorrectly, in that it should be -9999 instead
of -999?
Adam

Erik Noble wrote:
> Dear Adam,
> Thank you for pointing out the 1D requirement for ind.
>
> I used the dim_avg function earlier and wound up with negative values.
> I mistook this as a result of trying to average -9999 fill values. I
> see from your example that its not. But I still get negative values
> when I start out with only positive numbers. I'm trying to make my 3D
> array "r" (time, lat, lon) into a 1D array to plot as a bar graph,
> line plot, etc,...but I shouldn't be getting the negative numbers.
>
> Below is my reasoning. Am I using dim_avg wrong?
> Thank you,
> Erik
>
> ncl 0> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"
> ncl 1> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl"
> ncl 2> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"
> ncl 3> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/shea_util.ncl"
> ncl 4> load "$NCARG_ROOT/lib/ncarg/nclscripts/wrf/WRFUserARW.ncl"
> ncl 6> a=addfile("200609_CMORPH_3hr-025deg.nc","r")
> ncl 7> r=a->CMORPH
> ncl 8> printVarSummary(r)
>
>
> Variable: r
> Type: float
> Total Size: 60099840 bytes
> 15024960 values
> Number of Dimensions: 3
> Dimensions and sizes: [time | 240] x [lat | 222] x [lon | 282]
> Coordinates:
> time: [2006090100..2006093021]
> lat: [-20.125..35.125]
> lon: [-35.125..35.125]
> Number Of Attributes: 4
> lonFlip : longitude coordinate variable has been reordered via lonFlip
> long_name : merged microwave precipitation
> units : mm/hr
> _FillValue : -999
> ncl 9> max_r = max(r)
> ncl 10> min_r = min(r)
> ncl 11> print(min_r)
>
>
> Variable: min_r
> Type: float
> Total Size: 4 bytes
> 1 values
> Number of Dimensions: 1
> Dimensions and sizes: [1]
> Coordinates:
> (0) -9999
> ncl 12> print(max_r)
>
>
> Variable: max_r
> Type: float
> Total Size: 4 bytes
> 1 values
> Number of Dimensions: 1
> Dimensions and sizes: [1]
> Coordinates:
> (0) 50
> ncl 13> x = dim_avg(r)
> ncl 14> y = dim_avg(x)
> ncl 15> max_y = max(y)
> ncl 16> min_y = min(y)
> ncl 17> print(min_y)
> Variable: min_y
> Type: float
> Total Size: 4 bytes
> 1 values
> Number of Dimensions: 1
> Dimensions and sizes: [1]
> Coordinates:
> (0) -6503.074
> ncl 18> print(max_y)
>
>
> Variable: max_y
> Type: float
> Total Size: 4 bytes
> 1 values
> Number of Dimensions: 1
> Dimensions and sizes: [1]
> Coordinates:
> (0) -0.7426707
> ncl 19>
>
> On Fri, Jul 18, 2008 at 1:56 PM, Adam Phillips <asphilli_at_cgd.ucar.edu> wrote:
>> Hi Erik,
>>
>> dim_avg ignores all data that is set to _FillValue, as you can see here:
>>
>> ncl 0> a = (/1,2,3,4,5,-999/)
>> ncl 1> a@_FillValue = -999
>> ncl 2> print(dim_avg(a))
>> (0) 3
>>
>> So I don't know that you want to replace all the _FillValue data with 0's.
>>
>> Second, the ind documentation states that the input array must be
>> 1-dimensional, and you are inputting a 3-dimensional array. That is what the
>> "fatal:Number of dimensions in parameter (0) of (ind) is (3), (1)
>> dimensions were expected" error message means. Continuing with the
>> interactive ncl from above:
>> ncl 3> a(ind(ismissing(a))) = 0
>> ncl 4> print(a)
>>
>> Variable: a
>> Type: integer
>> Total Size: 24 bytes
>> 6 values
>> Number of Dimensions: 1
>> Dimensions and sizes: [6]
>> Coordinates:
>> Number Of Attributes: 1
>> _FillValue : -999
>> (0) 1
>> (1) 2
>> (2) 3
>> (3) 4
>> (4) 5
>> (5) 0
>>
>> Adam
>>
>>
>> Erik Noble wrote:
>>> Dear NCL,
>>> I was testing the ind and ismissing functions out in command line
>>> mode on my data to exclude the fill value when I do an average of the
>>> data (using dim_avg) . I followed examples #1 and #2 at
>>> http://www.ncl.ucar.edu/Document/Functions/Built-in/ind.shtml
>>> The ncl ind function page does not explain why i might be getting the
>>> error that i am getting. Could I have some help resolving this?
>>>
>>> Thank you for your time.
>>> -Erik
>>>
>>>
>>> ncl 15> printVarSummary(r)
>>>
>>>
>>> Variable: r
>>> Type: float
>>> Total Size: 60099840 bytes
>>> 15024960 values
>>> Number of Dimensions: 3
>>> Dimensions and sizes: [time | 240] x [lat | 222] x [lon | 282]
>>> Coordinates:
>>> time: [2006090100..2006093021]
>>> lat: [-20.125..35.125]
>>> lon: [-35.125..35.125]
>>> Number Of Attributes: 4
>>> lonFlip : longitude coordinate variable has been reordered via
>>> lonFlip
>>> long_name : merged microwave precipitation
>>> units : mm/hr
>>> _FillValue : -9999
>>> ncl 16> r@_FillValue = -9999
>>> ncl 17> r(ind(ismissing(r))) = 0
>>> fatal:Number of dimensions in parameter (0) of (ind) is (3), (1)
>>> dimensions were expected
>>> fatal:Execute: Error occurred at or near line 12
>>>
>>> ncl 18> ir =ind(.not.ismissing(r))
>>> fatal:Number of dimensions in parameter (0) of (ind) is (3), (1)
>>> dimensions were expected
>>> fatal:Execute: Error occurred at or near line 14
>>> _______________________________________________
>>> ncl-talk mailing list
>>> ncl-talk_at_ucar.edu
>>> http://mailman.ucar.edu/mailman/listinfo/ncl-talk
>> --
>> --------------------------------------------------------------
>> Adam Phillips asphilli_at_ucar.edu
>> National Center for Atmospheric Research tel: (303) 497-1726
>> ESSL/CGD/CAS fax: (303) 497-1333
>> P.O. Box 3000
>> Boulder, CO 80307-3000 http://www.cgd.ucar.edu/cas/asphilli
>>
>>

-- 
--------------------------------------------------------------
Adam Phillips			             asphilli_at_ucar.edu
National Center for Atmospheric Research   tel: (303) 497-1726
ESSL/CGD/CAS                               fax: (303) 497-1333
P.O. Box 3000				
Boulder, CO 80307-3000	  http://www.cgd.ucar.edu/cas/asphilli
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