2-D and 3-D Plots
Line Plots
To create two-dimensional line plots, use the plot
function. For example, plot the sine function over a linearly spaced vector of values from 0 to :
x = linspace(0,2*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--")
"r--"
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 on
. Until you use hold off
or close the window, all plots appear in the current figure window.
x = linspace(0,2*pi); y = sin(x); plot(x,y) hold on y2 = cos(x); plot(x,y2,":") legend("sin","cos") hold off
3-D Plots
Three-dimensional plots typically display a surface defined by a function in two variables, . For instance, calculate given row and column vectors x
and y
with 20 points each in the range [-2,2].
x = linspace(-2,2,20); y = x'; 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 connecting lines.
Multiple Plots
You can display multiple plots in different parts of the same window using either tiledlayout
or subplot
.
The tiledlayout
function was introduced in R2019b and provides more control over labels and spacing than subplot
. For example, create a 2-by-2 layout within a figure window. Then, call nexttile
each time you want a plot to appear in the next region.
t = tiledlayout(2,2); title(t,"Trigonometric Functions") x = linspace(0,30); nexttile plot(x,sin(x)) title("Sine") nexttile plot(x,cos(x)) title("Cosine") nexttile plot(x,tan(x)) title("Tangent") nexttile plot(x,sec(x)) title("Secant")
If you are using a release earlier than R2019b, see subplot
.