Note: This page has been translated by MathWorks. Please click here

To view all translated materals including this page, select Japan from the country navigator on the bottom of this page.

To view all translated materals including this page, select Japan from the country navigator on the bottom of this page.

To create two-dimensional line plots, use the `plot`

function. For example, plot the value of the sine function from 0 to :

x = 0:pi/100:2*pi; y = sin(x); plot(x,y)

You can label the axes and add a title.

xlabel('x') ylabel('sin(x)') title('Plot of the Sine Function')

By adding a third input argument to the `plot`

function, you can plot the same variables using a red dashed line.

`plot(x,y,'r--')`

The `'r--'`

string is a *line specification*. Each specification can include characters for the line color, style, and marker. A marker is a symbol that appears at each plotted data point, such as a `+`

, `o`

, or `*`

. For example, `'g:*'`

requests a dotted green line with `*`

markers.

Notice that the titles and labels that you defined for the first plot are no longer in the current *figure* window. By default, MATLAB® clears the figure each time you call a plotting function, resetting the axes and other elements to prepare the new plot.

To add plots to an existing figure, use `hold`

.

x = 0:pi/100:2*pi; y = sin(x); plot(x,y) hold on y2 = cos(x); plot(x,y2,':') legend('sin','cos')

Until you use `hold off`

or close the window, all plots appear in the current figure window.

Three-dimensional plots typically display a surface defined by a function in two variables, *z = f(x,y)* .

To evaluate *z*, first create a set of (*x,y*) points over the domain of the function using `meshgrid`

.

[X,Y] = meshgrid(-2:.2:2); Z = X .* exp(-X.^2 - Y.^2);

Then, create a surface plot.

surf(X,Y,Z)

Both the `surf`

function and its companion `mesh`

display surfaces in three dimensions. `surf`

displays both the connecting lines and the faces of the surface in color. `mesh`

produces wireframe surfaces that color only the lines connecting the defining points.

You can display multiple plots in different subregions of the same window using the `subplot`

function.

The first two inputs to `subplot`

indicate the number of plots in each row and column. The third input specifies which plot is active. For example, create four plots in a 2-by-2 grid within a figure window.

t = 0:pi/10:2*pi; [X,Y,Z] = cylinder(4*cos(t)); subplot(2,2,1); mesh(X); title('X'); subplot(2,2,2); mesh(Y); title('Y'); subplot(2,2,3); mesh(Z); title('Z'); subplot(2,2,4); mesh(X,Y,Z); title('X,Y,Z');

Was this topic helpful?