REBIN is an IDL routine that enables you to make a 2
dimension array larger or smaller (it also works on
multidimensional arrays). To use it to create a new
512
512 image (ndat) from a 6464 image (data) type:
IDL> ndat=rebin(data,512,512,/sample)
Note that the new x and y dimensions must be integral
multiples (or divisors) of the original array dimensions.