Grace is a WYSIWYG 2D plotting tool for the X Window System and M*tif,
successor of ACE/gr (Xmgr). A few of its features are:

    * User defined scaling, tick marks, labels, symbols, line styles,
	colors.
    * Batch mode for unattended plotting.
    * Read and write parameters used during a session.
    * Polynomial regression, splines, running averages, DFT/FFT,
	cross/auto-correlation.
    * Exports high-resolution graphics to (E)PS, PDF, MIF, and SVG
	formats
    * Supports cross-platform PNM, JPEG and PNG formats

While grace has a convenient point-and-click interface, most parameter
settings and operations are available through a command line interface
(found in Data/Commands).

WWW: http://plasma-gate.weizmann.ac.il/Grace/