Interpolating Without Changing the Mean
![Facebook](http://www.idlcoyote.com/images/xfacebook_32.png.pagespeed.ic.ZU_qt50XR6.png)
![Twitter](http://www.idlcoyote.com/images/xtwitter_32.png.pagespeed.ic.41Uof7Z4fm.png)
![RSS](http://www.idlcoyote.com/images/rss_32.png)
![Google+](http://www.idlcoyote.com/images/xgplus_32.png.pagespeed.ic.Y_sKm-zOQt.png)
QUESTION: When I interpolate an array with, say, Congrid, the mean of the interpolated array is different from the mean of the original array. Is there a function in IDL that can perform the rebinning or interpolation without changing the mean or flux of the result?
ANSWER: Wayne Landsman reports that the FRebin command in the NASA Astronomy Library has been written specifically to perform this function.
Version of IDL used to prepare this article: IDL 8.2.1.
Copyright ©
1996–2018 Fanning Software Consulting, Inc.
Written: 19 October 2012