Making a visible presentation of numerical data, particularly a graphical one. This might include anything from a simple X-Y graph of one dependent variable against one independent variable to a virtual reality which allows you to fly around the data.
Gnuplot is the Free Software Foundation's utility for producing various kinds of graphs.
Usenet newsgroup: news:comp.graphics.
The Computer Graphics Resource Listing contains pointers to several visualisation tools.
Electronic Visualization Laboratory, University of Illinois at Chicago.