Graphing Packages

Spreadsheets

Many spreadsheets such as Excel and Quatro Pro can also be used for simple graphing. These packages are widely available for Mac and PC platforms and vary in how they are used. However, most have features for multiple line plots, scatter plots with or without error bars, histograms, and contour and surface plots.

Data Manipulation Programs

There also exist commercial packages designed to have the ease of spreadsheet use with advanced graphing capabilties, enhanced ability to handle 3-D graphics and enhanced numerical support. Examples of these are SigmaPlot and Axum. These tools have extended data reduction capabilities and many of these packages will perform least squares analyses and other fitting routines for data.

Gnuplot

At its simplest, assuming we have a set of data, a gnuplot session might look like this:

gnuplot> plot "test.dat" with lines

This command tells gnuplot to find a set a data, and make a plot of that data using lines (versus points or dots).

A variety of other examples, with the resulting plots, are included here:

simple gnuplot demo

# gnuplot> set term 
# gnuplot> load 'simple.dem'
#
set samples 50
plot [-10:10] sin(x),atan(x),cos(atan(x))

set samples 100
plot [-pi/2:pi] cos(x),-(sin(x) > sin(x+1) ? sin(x) : sin(x+1))

set samples 200
plot [-3:5] asin(x),acos(x)

plot [-30:20] besj0(x)*0.12e1 with impulses, (x**besj0(x))-2.5 with points

set samples 400
plot [-10:10] real(sin(x)**besj0(x))

plot [-5*pi:5*pi] [-5:5] real(tan(x)/atan(x)), 1/x

set autoscale
set samples 800
plot [-30:20] sin(x*20)*atan(x)

f(x) = x/100
plot [-19:19] '1.dat'with impulses ,'2.dat' thru f(x) ,'3.dat' with lines

# undo what we have done above
set samples 160
set xrange [-10:10]
set autoscale xy

An interactive Web interface to Gnuplot is available here.