When a large region of data is displayed as an image there is an upper limit of the maximum number of pixels to be output by the graphics system to a PostScript file20. If necessary, prior to display, the region is automatically re-binned to a smaller size. The data is re-binned by an equal factor in both directions, and scaled by the number of re-binned pixels, so the range is approximately the same as the range of the full data. This both reduces image file size, and makes printing faster.
The upper limit may changed by the user, so that higher or lower resolution images may be printed.