MATLAB drawing summary

The most commonly used drawing function in MATLAB is plot. According to different coordinate parameters, it can draw different curves on a two-dimensional plane.

plot function

Calling format : plot (x, y) where x and y are coordinate vector
functions Function : draw XY two-dimensional curve with vector x as X axis and vector y as Y axis

Example 1: Draw a sine curve in the interval [0,2π] y = sin (x)

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

Results:

Example 2 Simultaneous drawing of sine curve y = sin (x) and cosine function y = cos (x) in the interval [0,2π]

   x=0:pi/100:2*pi;
   y1=sin(x);
   y2=cos(x);
   plot(x,y1,x,y2)

Result:

Adding some parameters to the plot drawing instruction can draw graphics with different colors and different line types

Example 3 Simultaneously draw sinusoids y = sin (x) and cosine function y = cos (x) of different line types and different colors in the interval [0,2π]

 x=0:pi/100:2*pi;
 y1=sin(x);
 y2=cos(x);
 plot(x,y1,'k:',x,y2,'b-')
 

result:

The line style and color of each curve is specified by the string 'cs' where c is the color s is the line style
Correspondence between color and line type:

Color symbol	colour	Line symbol	Linear
and	yellow	.	point
m	purple	- -	dotted line
r	red	+	plus
g	green	*	Asterisk
b	blue	-	solid line
w	white	:	Dotted line
k	black	.-	Dotted line

Set the coordinate axis

When drawing a graph, the system automatically gives the coordinate axis of the graph. The user can also use the axis function to reset it.

Example 4 Draw a sine curve in the coordinate range 0 ≤ x ≤ 2π, −1 ≤ y ≤ 2

	x=linspace(0,2*pi,60);
	y=sin(x); %生成含有 60 个数据元素的向量 x
	plot(x,y);
	axis([0,2*pi,-1,2]); %设定坐标范围

The result is:

axis function call

form	Features
axis([xmin xmax yminmax])	Set the maximum and minimum values ​​of the coordinate axis
axis ('auto')	Return the coordinate system to the automatic default state
axis(‘off’)	Turn off the coordinate system
axis(‘on’)	Display coordinate system

Add legend

x=0:pi/100:2*pi; 
y1=sin(x);
y2=cos(x);
plot(x,y1,'k:',x,y2,'b-')
title('sine and cosine curves');
xlabel('independent variable X');
ylabel('dependent variable Y');
text(2.8,0.5,'sin(x)');
text(1.4,0.3,'cos(x)');
legend('sin(x)','cos(x)');

The result is:

subplot function-draw multiple parallel graphs

Form: subplot (m, n, p) The
effect is: the drawn sub-plot has m lines, each line has n figures, and the currently drawn figure is the p-th
such as subplot (4,2,3) refers to co-drawing Four rows of subgraphs, each row has 2 graphs, the graph currently being drawn is the third one, which is the first one in the second row

Example:

x=linspace(0,2*pi,60);
y=sin(x);
z=cos(x);
t=sin(x)./(cos(x)+eps);
ct=cos(x)./(sin(x)+eps);
subplot(2,2,1);
plot(x,y);
title('sin(x)');
subplot(2,2,2);
plot(x,z);
title('cos(x)');
subplot(2,2,3);
plot(x,t);
title('tangent(x)');
subplot(2,2,4);
plot(x,ct);
title('cotangent(x)');

The effect is:

Two-dimensional drawing summary: