"The human eye is incredibly good at recognizing complex
behavior and spotting trends and patterns in visually displayed
data. If any dataset is larger than about a dozen points, a graph
is helpful; if the dataset exceeds a few thousand points, a graph
becomes a necessity.
"For simple x-y plots, gnuplot is often the first choice. For
more complicated problems you can use xmgrace and other plotting
tools. However, most simple curve plotters are insufficient for
plotting two-dimensional data or for exerting detailed control over
a complicated graph. Examples of complicated graphs include
specialized bar-and-whiskers plots, time-series with sophisticated
error bars, color encodings and density plots, and many other
"This is where Perl/Tk shines. Chances are, you're already using
Perl for data manipulation and extraction. Perl/Tk provides Perl
bindings for the Tk GUI toolset and is possibly one of the
easiest-to-use widget sets around..."