Plot from “Data”
• MATLAB does not understand functions
𝑓(𝑡) = sin(2𝜋𝑡)
• Strategies
- Generate the numeric values of a function over a specific range.
- Display the data “points” in a graphical way.
plot()
• plot(x,y) plots each vector pairs (x,y)
• plot(y) plots each vector pairs (x,y),where x=[1…n], n=length(y)
• Example:
plot(cos(0:pi/20:2*pi));
hold on/off
• Use hold on to have both plots in one figure.
Plot Style
• plot(x,y,'str') plots each vector pairs (x,y) using the format defined in str (check linespec)
legend()
• Add legend to graph
legend('L1',...)
• Position adjustment
title() and label()
• title()
• xlabel()
• ylabel()
• zlabel()
text() and annotation()
• Text with mathematical expression using LaTex
Exercise
• Plot 𝑓 as a black line and 𝑔 as a series of red circles for the range t = 1 to 2 in one figure
𝑓 = and 𝑔 = sin(2𝜋𝑡)
• Label each axis, and add title and legend
Figure Adjustment
• Several properties:
• Font
• Font size
• Line width
• Axis limit
• Tick position
• Tick label
Graphical Objects
• A figure is composed of many objects
Figure Properties
![]()
屏幕截图(82).png
Modifying Properties of An Object
• Strategy:
- Identify the “handle” of an object
- Fetch or modify the object’s properties
• For example, to change the limits of the x-axis:
- Find the handle of the x-axis
- Modify the limits
1. Identifying the Handle of An Object
• Upon creation:
h = plot(x,y);
• Utility functions:
Fetching or Modifying Properties
• To fetch properties, use
get( )
• To modify properties, use
set( )
Getting Object Properties
• Getting properties of a graphical object: get( )
Setting Axes Limits
