| Re: averaging w.r.t time resolution [message #87240 is a reply to message #87239] |
Mon, 20 January 2014 06:53   |
Matthew
Messages: 18
Registered: February 2006
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Junior Member |
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> I have a data array for 86400 seconds each day (i.e., @ 1 second resolution). Is there any direct function in IDL which can be used to get the different time resolution (i.e., say 1 minute or 5 minute or 15 minute or 1 hour etc.) averages of the data array with respective time stamp automatically?
I can think of three options:
1. Rebin + Interpol
IDL> data = randomu(1, 86400)
IDL> time = findgen(86400)
IDL> new_time = rebin(time, 17280) ;Every ~5 minutes
IDL> new_data = interpol(data, time, new_time)
http://exelisvis.com/docs/REBIN.html
http://exelisvis.com/docs/INTERPOL.html
2. Congrid + Interpol
IDL> data = randomu(1, 86400)
IDL> time = findgen(86400)
IDL> new_time, congrid(time, 12342) ;Every ~7 minutes
IDL> new_data = interpol(data, time, new_time)
http://exelisvis.com/docs/CONGRID.html
Note that rebin and congrid do different things. Rebin averages while Congrid resamples.
3. Interpol + a little work
Might be helpful:
linspace https://klassenresearch.orbs.com/Emulate+linspace+and+logspa ce
or
In IDL 8.3 use findgen or the colon operator
http://www.exelisvis.com/docs/Other_Operators.html
http://www.exelisvis.com/docs/FINDGEN.html
IDL> data = randomu(1, 86400)
IDL> old_time = findgen(86400)
IDL> nMinute = 7 ;Minute intervals
IDL> nTimes = 86400/nMinute ;Number of time stamps
IDL> new_time = findgen(nTimes)/(nTimes-1) * 86400
IDL> new_data = interpol(data, old_time, new_time)
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