Re: missing values

From: Mary Haley <haley_at_nyahnyahspammersnyahnyah>
Date: Fri Jan 04 2013 - 13:54:46 MST

Rafael,

If you are getting one single missing value, then something is likely wrong with the data you are passing in.

Did you look at pocean to make sure it is okay?

printVarSummary(pocean)
print("min/max pocean = " + min(pocean) + "/" + max(pocean))

--Mary

On Jan 4, 2013, at 12:41 PM, rafael dido wrote:

> Hallo NCL Users,
>
> Thanks for the response,
>
> I meant, why did the result of the areal average either for land masking or ocean masking in this case (precipitation over the ocean or land) is equal to -999. I noticed in the previous email the the print value for "ave" which is an areal average for sea is equal to missing value.
>
> What should i do thus i will obtain the real value of this calculation.
>
> my code
> [snip]
>> f = addfile("/projekt1/precip_ocean.nc","r") ; Read in first time step and
>> pocean = f->psea(:,{-10:10},:)
>> pocean@_FillValue = pocean@missing_value
>> pocean@_FillValue = -999
>> printVarSummary(pocean)
>>
>> rad = 4.0*atan(1.0)/180.0
>> clat = cos(lat*rad)
>> ocean = dim_avg_Wrap( pocean(lat|:, lon|:, time|:) )
>> Ave = wgt_areaave(ocean, clat, 1.0, 1)
>> print(ave)
>>
>> [snip]
>>
>> --------------------------Result-------------------
>> Variable: Ave
>> Type: float
>> Total Size: 4 bytes
>> 1 values
>> Number of Dimensions: 1
>> Dimensions and sizes: [1]
>> Coordinates:
>> Number Of Attributes: 1
>> _FillValue : -999
>> (0) -999 <------------------------------Areal Average of precipitation over the Ocean
>
>
> Thanks,
> Rafael
>
>
>
>
>
>
>
>
>
>
> On Sat, Jan 5, 2013 at 3:57 AM, Mary Haley <haley@ucar.edu> wrote:
> Rafael,
>
> I'm not sure what the problem is. Do you mean that you don't want a
> _FillValue of -999?
>
> If so, then in your script, you changed the _FillValue attribute to have a
> value of -999, which means when you take the average, it will also
> have a _FillValue attribute of -999.
>
> If you don't want -999 as a _FillValue, then remove this line:
>
>
>> pocean@_FillValue = -999
>
> --Mary
>
>
> On Jan 4, 2013, at 10:49 AM, rafael dido wrote:
>
>> Hi NCL,
>>
>> I have nc file containing missing value indicated by "_"
>>
>> dimensions:
>> lon = 360 ;
>> lat = 181 ;
>> time = UNLIMITED ; // (4383 currently)
>> variables:
>> double lon(lon) ;
>> lon:units = "degrees_east" ;
>> lon:modulo = 360. ;
>> lon:point_spacing = "even" ;
>> lon:axis = "X" ;
>> double lat(lat) ;
>> lat:units = "degrees_north" ;
>> lat:point_spacing = "even" ;
>> lat:axis = "Y" ;
>> double time(time) ;
>> time:units = "hours since 1997-01-01 00:00:00" ;
>> time:time_origin = "01-JAN-1997 00:00:00" ;
>> time:axis = "T" ;
>> float psea(time, lat, lon) ;
>> psea:missing_value = -1.e+34f ;
>> psea:_FillValue = -1.e+34f ;
>> // global attributes:
>> :Conventions = "CF-1.0" ;
>> data:
>>
>> psea =
>> _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _,
>> _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _,
>> 0.02250607, 0.5173603, 0, 0, 0, 0, 0, 0, 0, 0.01500405, 0, 0, 0, 0, 0, 0,
>> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
>> _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _,
>> _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, 0, 0, 0.4348826, 0.05248583,
>> 3.899931, 24.72732, 53.44849, 21.48183, 11.3707, 3.757559, 0.0299919,
>>
>> [SNIP]
>>
>> Once, I calculated the average for a specific domain i got the result is -999 as
>> i set my command as follow:
>>
>> f = addfile("/projekt1/precip_ocean.nc","r") ; Read in first time step and
>> pocean = f->psea(:,{-10:10},:)
>> pocean@_FillValue = pocean@missing_value
>> pocean@_FillValue = -999
>> printVarSummary(pocean)
>>
>> rad = 4.0*atan(1.0)/180.0
>> clat = cos(lat*rad)
>> ocean = dim_avg_Wrap( pocean(lat|:, lon|:, time|:) )
>> Ave = wgt_areaave(ocean, clat, 1.0, 1)
>> print(ave)
>>
>> === [executed]
>> Variable: Ave
>> Type: float
>> Total Size: 4 bytes
>> 1 values
>> Number of Dimensions: 1
>> Dimensions and sizes: [1]
>> Coordinates:
>> Number Of Attributes: 1
>> _FillValue : -999
>> (0) -999
>>
>>
>> Is there any hints how to handle this problem in NCL? When I used another language program,
>> and I do not get any problem to calculate this average.
>>
>>
>> Thanks
>>
>> RF.
>>
>>
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Received on Fri Jan 4 13:56:03 2013

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