Re: MISSING function

[Ansley Manke <ansley.b.manke@xxxxxxxx>]

Hi Yogesh,
To change or set the missing-value flag of a variable in a netCDF file, 
use the command    SET VAR/BAD=

  SET VAR/BAD=-9999 co2

If there was already a missing_value or _FillValue attribute for co2 in 
the netCDF file, then previously missing data is still missing, and the 
flag for all missing values is now -9999.


The MISSING function does not set the missing-value flag.  It replaces 
the missing values in a variable with the given value.  So, if you have 
a variable B with values already marked as missing, and you wanted to 
fill in the missing values with, say, zero, you could do

   LET a = MISSING(b, 0)

And the variable A would have all the valid values of B, and where B was 
invalid, it would contain the value 0.

Ansley


Yogesh K. Tiwari wrote:

> Hello Ferret Users,
>
> I have netcdf file and after doing ncdump of a variable co2, some of 
> the values are -9999.
>
> I want to treat this value as missing value.
>
> I tried to teach ferret this missing value by using the MISSING 
> function like :-
>
> let a = -9999
>       let missing_default = `a, RETURN=bad`
>
> let co2_default =  MISSING(co2, missing_default)
>
>
> But the result still includs the missing value -9999 in the shade plot 
> and the CO2 values are -200,-300 like that whereas my data is ok and 
> have no negative co2 value.
>
> Whether I did correctly ?? then why result dosen't chang with or 
> without missing function.
>
> Whether ferret like -9999 as missing value ?
>
> Many thanks in advance for your help.
>
> Regards,
> Yogesh