In the usual case that the image dimensions are hundreds of pixels, colimplot can take quite a while to run if a pgplot output is selected. On the other hand it is often necessary to make several trials before one arrives at parameter values that produce the desired output, because the initial appearence on any pgplot output device may not at first be very pleasing, due partly to the aforementioned limit on the number of colours available. This adds up to an irritating situation for the user. A way around this is to produce an intermediate output with a reduced number of image pixels, via the parameters rebinimage, rebinstyle, dividexby, divideyby, newnxbins and newnybins. The way these work is probably best illustrated by a couple of examples. So, to rebin the intermediate image to 40 in the x direction by 50 in y, use the following values:
rebinimage=yes
rebinstyle=tonumber
newnxbins=40
newnybins=50
If, on the other hand, you wish to rebin by dividing the number of x pixels by 3.3 and the number of y by 10, use the following values:
rebinimage=yes
rebinstyle=divideby
dividexby=3.3
divideyby=10
Note that it is only possible to decrease the resolution of the image. An error will result if the requested number of bins in either direction is larger than the relevant dimension of the input images.