| Re: replacing "NAN" values using interpolation in IDL [message #82782] |
Thu, 17 January 2013 07:05  |
Jeremy Bailin
Messages: 618
Registered: April 2008
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Senior Member |
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On 1/17/13 4:02 AM, idlhelp wrote:
> Dear all, I have an data array. I have many "NaN" values. I want to replace those "NaN" values by the nearby values either using interpolation. Is there any way to do that in IDL.
>
> Thanks in advance
>
Yes, there is.
Oh, you want to know how? ;-)
I would do something like this, if I had an array of locations x and a
data array data:
; sample data
x = [1., 2., 3., 5., 7., 7.5, 9., 12., 12.1]
data = [0., !values.f_nan, 10., 15., !values.f_nan, !values.f_nan, 5.,
4., 5.]
; figure out where there are NaNs and where the useful data are
gooddata = where(data eq data, ngooddata, $
comp=baddata, ncomp=nbaddata)
; interpolate at the locations of the bad data using the good data
if nbaddata gt 0 then begin
data[baddata] = interpol(data[gooddata], x[gooddata], x[baddata])
endif
-Jeremy.
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| Re: replacing "NAN" values using interpolation in IDL [message #82974 is a reply to message #82782] |
Mon, 28 January 2013 09:27  |
abc
Messages: 46
Registered: March 2011
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Member |
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On Thursday, January 17, 2013 4:05:11 PM UTC+1, Jeremy Bailin wrote:
> On 1/17/13 4:02 AM, idlhelp wrote:
>
>> Dear all, I have an data array. I have many "NaN" values. I want to replace those "NaN" values by the nearby values either using interpolation. Is there any way to do that in IDL.
>
>>
>
>> Thanks in advance
>
>>
>
>
>
> Yes, there is.
>
>
>
> Oh, you want to know how? ;-)
>
>
>
> I would do something like this, if I had an array of locations x and a
>
> data array data:
>
>
>
> ; sample data
>
> x = [1., 2., 3., 5., 7., 7.5, 9., 12., 12.1]
>
> data = [0., !values.f_nan, 10., 15., !values.f_nan, !values.f_nan, 5.,
>
> 4., 5.]
>
>
>
> ; figure out where there are NaNs and where the useful data are
>
> gooddata = where(data eq data, ngooddata, $
>
> comp=baddata, ncomp=nbaddata)
>
>
>
> ; interpolate at the locations of the bad data using the good data
>
> if nbaddata gt 0 then begin
>
> data[baddata] = interpol(data[gooddata], x[gooddata], x[baddata])
>
> endif
>
>
>
> -Jeremy.
Thanks Jeremy, but the problem I am having is that I don't have any sample data 'x'. I have only 'data' and want to use that 'data' file again for interpolating and replacing the NaN value. Any Idea how to do that.
thanks
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