### Postscript

In order to reduce the size of postscript files, the gray value and not all three calculated r,g,b values are written to the file. Therefore the analytical formulae are coded directly in the postscript language as a header just before the pm3d drawing, see /g and /cF definitions. Usually, it makes sense to write therein definitions of only the 3 formulae used. But for multiplot or any other reason you may want to manually edit the transformations directly in the postscript file. This is the default option nops_allcF. Using the option ps_allcF writes postscript definitions of all formulae. This you may find interesting if you want to edit the postscript file in order to have different palettes for different surfaces in one graph. Well, you can achieve this functionality by multiplot with fixed origin and size.

If you are writing a pm3d surface to a postscript file, it may be possible to reduce the file size by up to 50% by the enclosed awk script pm3dCompress.awk. If the data lies on a rectangular grid, even greater compression may be possible using the script pm3dConvertToImage.awk. Usage:

       awk -f pm3dCompress.awk thefile.ps >smallerfile.ps
       awk -f pm3dConvertToImage.awk thefile.ps >smallerfile.ps