| meanclip [message #82319] |
Thu, 06 December 2012 03:13  |
Charlie Paul D'auria
Messages: 3
Registered: November 2012
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Junior Member |
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Hi everyone.
I was just wondering if anyone can guide me in using meanclip.pro? I'm am an IDL beginner and the online documentation is sparse.. (I don't get it)
I have a double array of 2 columns and 1439 rows.
I'd like to use this program to clip data that is a certain amount of sigma away from the last value and then plot it. I am also using the Poly fit routine if this is relevant.
Any help would be great appreciated!
Charlie
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| Re: meanclip [message #82367 is a reply to message #82319] |
Sat, 08 December 2012 14:32  |
wlandsman
Messages: 743
Registered: June 2000
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Senior Member |
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One problem with using meanclip.pro for your example, is that it determines outliers by comparing with the mean of *all* the data. But your data presumably has real trends, (which you are trying to determine with poly_fit).
Better would be to use "robust" polynomial fitting, in which outliers are determined by their deviation from a polynomial fit. This what the program robust_poly_fit.pro does.
http://idlastro.gsfc.nasa.gov/ftp/pro/robust/robust_poly_fit .pro
--Wayne
On Saturday, December 8, 2012 3:32:57 PM UTC-5, Charlie Paul D'auria wrote:
>
> The array contains data relating to the flux versus time of an astronomical event. The data shows strange characteristics such as dips, which I am hoping to remove by a method other that just 'cutting' them out by eye. I was hoping to use a program that discards data that is outside an allowed limit from the previous data point.
>
>
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> I have used poly fit to fit a trend line to see if the data fits a certain gradient.
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> Anyway, i'll give what i've got a go.
>
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> Charlie
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| Re: meanclip [message #82369 is a reply to message #82319] |
Sat, 08 December 2012 12:32 |
Charlie Paul D'auria
Messages: 3
Registered: November 2012
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Junior Member |
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On Thursday, 6 December 2012 11:13:48 UTC, Charlie Paul D'auria wrote:
> Hi everyone.
>
>
>
> I was just wondering if anyone can guide me in using meanclip.pro? I'm am an IDL beginner and the online documentation is sparse.. (I don't get it)
>
>
>
> I have a double array of 2 columns and 1439 rows.
>
>
>
> I'd like to use this program to clip data that is a certain amount of sigma away from the last value and then plot it. I am also using the Poly fit routine if this is relevant.
>
>
>
> Any help would be great appreciated!
>
>
>
> Charlie
Thanks for the help so far, and sorry for the lack of details!!
Wayne, what you've written seems great, I will try this.
The array contains data relating to the flux versus time of an astronomical event. The data shows strange characteristics such as dips, which I am hoping to remove by a method other that just 'cutting' them out by eye. I was hoping to use a program that discards data that is outside an allowed limit from the previous data point.
I have used poly fit to fit a trend line to see if the data fits a certain gradient.
Anyway, i'll give what i've got a go.
Charlie
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