Basic Usage of GnuPlot

Hyun Hee Shim Department of Physics Kangwon National University

What is GnuPlot?

GnuPlot is a command-driven interactive function plotting program.

• Introduction

• Operation

1. Plotting of two dimensional functions and data points in many

different style.

2. Plotting of three dimensional data points and surfaces in many

different style.

Starting and Quitting the GnuPlot

• Starting : To start the GunPlot under Unix , just type the command

“gnuplot”.

• Quitting : To exit GnuPlot, you can type either quit, exit or

simply q.

Basic screen of GnuPlot

Menubar in the Gnuplot

File Plot Expressions

On the menu bar, you can use the source wish to select.

Function

General Axis

Chart

3D Style

Plotting function

To start exploring GnuPlot, try the following command.

: The first plot command produces a plot of function.

In the first example, the range of x is not specified, so GnuPlot use its default range of (-10,10).

• Plot Function

Ex) plot cos(x)

Ex) plot [-pi : pi] sin(x**2),cos(exp(x))

The second plot command produces a plot of the functions sin and cos on the same graph, with x in the range (-π, π).

2xxe

In the second example, the phrase [-pi:pi] following plot tells GnuPlot to produce the plot with x in the range This tells GnuPlot to plot both functions on the same plot.       

• Plot interval function

Plotting the data

gnuplot> plot “map.dat” u 1:2 t “” w p 3

Represented data

Explanation : Point style using 3 color is pressed w p 3.

: File for map.dat plot using data.

: First column equal to x,second column equal to y. (u 1:2)

Summary

• GnuPlot is function plotting program using the command.

• GnuPlot can plot data.