Gnuplot is a freeware program to plot data. You will use Preplot to reformat your analytical results so that Gnuplot can create graphical results. Throughout the examples, we will refer to the program as Gnuplot, although it may have different names on different systems. For example, it is called gnuplot 3.7.1c on my Macintosh, while it comes as WGNUPLOT.EXE for Windows machines. Under UNIX, it will probably be called gnuplot and reside in /usr/local/bin.
Gnuplot will generally be run after Preplot and will need to load the plot control file created by Preplot. Let's suppose that the plot control file is stem.plt. If you are on a Macintosh, you will double click the Gnuplot binary and then use the ``File'' menu and ``Open'' to navigate and load stem.plt. This is similar to Windows except that you start up WGNUPLOT.EXE.
On a UNIX machine, you can load the plot control file from the command line:
% gnuplot stem.pltor start up Gnuplotand load the file with
.
For all the following examples, we will simply say view the results using Gnuplot. If the plot control file has more than one graph, you will need to press return to see the next one in the sequence. Also, the only way to go back is to finish viewing all the graphs and reload the plot control file.