PLplot is a scientific plotting package which is relatively small,
portable, and freely distributable. It has a wide range of plot types
including line (linear, log), contour, 3D, fill, and almost 1000
characters (including Greek and mathematical) in its extended font
set.  The package is designed to make it easy to quickly get graphical
output; only a handful of function calls is typically required.  For
more advanced use, virtually all aspects of plotting are configurable.

PLplot includes drivers for postscript, xfig, HPGL, impress, native
meta-file, X-Window, Xterm, Tcl/Tk, Tektronix terminals, vt100/tek and
vt320/tek emulators, and others.

The PLplot package includes interfaces for the Fortran, C, C++, and
Tcl languages. There is also a Tcl based interpreter (pltcl), allowing
interactive plotting.