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Re: Daily to monthly [message #89888 is a reply to message #89881]

Wed, 17 December 2014 12:54

Craig Markwardt
Messages: 1869
Registered: November 1996

Senior Member

On Tuesday, December 16, 2014 1:21:46 PM UTC-5, mani...@gmail.com wrote:
> Hi Craig,
> I need Monthly means where missing values are taken care of

Average = sum / n_points

The only trick is that n_points could be different depending on missing data. So if I had an array of values DATA[*,*] where DATA[i,j] is the ith position on the jth day, and missing value is -999, I could sum them like this,

tot = 0 ;; cumulative sum of data values
npt = 0 ;; cumulative sum of number of good data values
for j = 0, NDAYS-1 do begin
mask = data[*,j] NE -999 ;; mask of good values only, 1=good
npt = npt + mask ;; add to number of good values
tot = tot + (data[*,j]*mask) ;; add good vals to cumulative data sum
endfor

;; Compute average
av = tot / npt

Craig

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[Message index]

		Daily to monthly By: manikbali on Mon, 15 December 2014 20:10
		Re: Daily to monthly By: Craig Markwardt on Tue, 16 December 2014 09:49
		Re: Daily to monthly By: manikbali on Tue, 16 December 2014 10:21
		Re: Daily to monthly By: Craig Markwardt on Wed, 17 December 2014 12:54
		Re: Daily to monthly By: lecacheux.alain on Fri, 19 December 2014 01:31

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