postscript

This section is only relevant to output from set term postscript color. When the palette is defined using set palette rgbformulae, gnuplot writes a postscript implementation of the required analytical formulae as a header just before a pm3d drawing (see /g and /cF definitions). Usually, it makes sense to write definitions of only the 3 formulae used in the palette. This is the default option nops_allcF. The option ps_allcF instead writes definitions of all 36 formulae. This allows you to edit the postscript file in order to have different palettes for different surfaces in one graph.

If you write a pm3d surface to a postscript file, it may be possible to reduce the file size by running the awk script pm3dCompress.awk afterward. If the data lies on a rectangular grid, even greater compression may be possible using the awk script pm3dConvertToImage.awk. Both scripts are distributed with gnuplot. Usage:

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