Some of the options are:

    *  The utility ctrans(1) in the NCAR Graphics package -- available
       via licencing and a fee:

	    scdinfo@ncar.ucar.edu

    *  The C program gplot(1) from the Pittsburgh Supercomputing 
       Center -- available via anonymous FTP:

	    host: ftp.psc.edu [128.182.62.148]
	    file: pub/gplot/gplot.tar.Z

       I believe this package contains the X viewing program gplotm.

    *  The GKSM-to-PostScript program gksm2ps(1) from Larry Oolman 
       <oolman@coyote.uwyo.edu> -- available via anonymous FTP:

	    host: screamer.uwyo.edu.
	    file: pub/gksm2ps.tar.Z

	    >Here is the disclaimer.  At this time the translator is
	    >only partially complete.  It works well for the
	    >applications we use for at Wyoming.  I would be happy
	    >to consider adding additional features but I don't make
	    >any guarantees.  --Larry Oolman

I think I'd go with gplot(1).
