Plot from “Data”

• MATLAB does not understand functions
  𝑓(𝑡) = sin(2𝜋𝑡)
• Strategies

1. Generate the numeric values of a function over a specific range.
2. 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.

在一张图片上绘制两个图

Plot Style

• plot(x,y,'str') plots each vector pairs (x,y) using the format defined in str (check linespec)

绘图风格

legend()

• Add legend to graph
  legend('L1',...)
• Position adjustment

带label的函数图形

label的实现语法

title() and label()

• title()
• xlabel()
• ylabel()
• zlabel()

屏幕截图(69).png

x,y轴的名称及图片标题

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

屏幕截图(81).png

Figure Properties

屏幕截图(82).png

Modifying Properties of An Object

• Strategy:

1. Identify the “handle” of an object
2. Fetch or modify the object’s properties

• For example, to change the limits of the x-axis:

1. Find the handle of the x-axis
2. 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