The WagSoft System Network Editor is software that lets you create and modify system networks (from Systemic Functional Grammar), and save them as images to include in your Word documents or web page. The tool is ideal for those preparing diagrams for publications.
Free. Currently available for Windows and Macintosh (MacOSX 1.3.9 or higher), but ask if you want it for for Linux.
DOWNLOAD:
The Macintosh version may have problems
related to saving as SVG.
For any problems, contact the author: Mick O'Donnell.