How do I combine multiple plots in one graph?

Hi, is there somewhere I can see some examples of scripts that result in multiple plots on one graph?

I know the 'hold' function is part of how to do it, but I'm very new to Matlab and I really need to see some full examples.

If someone could point me towards some that'd be great.

[tayyaba khurshid]

snr=0:1:15;
for ii=1:length(snr)
    x=randint(1,100000); % Generating bits
    y=pskmod(x,2); % Generating BPSK modulated data
    ynoisy=awgn(y,snr(ii)); % Adding AWGN noise to data
    z=pskdemod(ynoisy,2); % Demodulating
    error(ii)=length(find(x-z~=0));
end
semilogy(snr,error)
hold
snr=0:1:15;
for ii=1:length(snr)
    x=randint(1,100000); % Generating bits
    y=pskmod(x,4); % Generating QPSK modulated data
    ynoisy=awgn(y,snr(ii)); % Adding AWGN noise to data
    z=pskdemod(ynoisy,4); % Demodulating
    error(ii)=length(find(x-z~=0));
end
semilogy(snr,error)
grid

[Chiemela Victor Amaechi]

You can use this code, but to have multiple plots, you need the subplot which is used as follows:

% Code used in my paper on design of composite riser
% Create a vertical bar chart using the bar function
figure
subplot(2,3,1) % add fourth plot in 2 x 3 grid
bar(1:18, [FibreControl' FibreAxial'], 1)
% Add title and axis labels
title('(a)')
xlabel('Composite Riser Layers')
ylabel('Stress in Fibre Direction (MPa)')
% Add a legend
legend('[1.58:1.62:1.86]', '[1.84:1.62:1.86]')
% Set the axis limits
set(gca, 'XTick', 1:18)
set(gca, 'XLim', [0,19])
set(gca, 'Fontsize', 8)
subplot(2,3,2) % add first plot in 2 x 3 grid
bar(1:18, [FibreControl' FibreAngled'], 1)
% Add title and axis labels
title('(b)')
xlabel('Composite Riser Layers')
ylabel('Stress in Fibre Direction (MPa)')
% Add a legend
legend('[1.58:1.62:1.86]', '[1.58:1.88:1.86]')
% Set the axis limits
set(gca, 'XTick', 1:18)
set(gca, 'XLim', [0,19])
set(gca, 'fontname','arial','fontsize',8,'linewidth',1)
subplot(2,3,3) % add second plot in 2 x 3 grid
bar(1:18, [FibreControl' FibreHoop'], 1)
% Add title and axis labels
title('(c)')
xlabel('Composite Riser Layers')
ylabel('Stress in Fibre Direction (MPa)')
% Add a legend
legend('[1.58:1.62:1.86]', '[1.58:1.62:1.60]')
% Set the axis limits
set(gca, 'XTick', 1:18)
set(gca, 'XLim', [0,19])
set(gca, 'Fontsize', 8)

[Mebin Cherian]

Hey, @tayyaba, I have to plot graphs of various iterations into the same graph, and the labels are written during each iteration. My problem is that the legend gets overwritten each time instead of being appended to the already existing legend. soln?

semilogy(snr,error(i));

Label=append('Error',error(i));

label(Label);

hold on;

Answer 1

[Chandra Kurniawan]

To combine multiple plots in one graph, use the “hold on” command, such as:

 plot(1:10)
 hold on 
 plot(11:20)
 hold off

For more information, see:

https://www.mathworks.com/help/matlab/creating_plots/combine-multiple-plots.html

[Walter Roberson]

The alternative to "hold on" that would be applicable to this example is

plot(t,x,'r',t,y,'b')

[Ina Panci]

Hello, what other letters can we use if we have more than two functions to plot?

[Cleat Zeiler]

This is the list from the help call:

Various line types, plot symbols and colors may be obtained with

plot(X,Y,S) where S is a character string made from one element

from any or all the following 3 columns:

b blue . point - solid

g green o circle : dotted

r red x x-mark -. dashdot

c cyan + plus -- dashed

m magenta * star (none) no line

y yellow s square

k black d diamond

w white v triangle (down)

^ triangle (up)

< triangle (left)

> triangle (right)

p pentagram

h hexagram

Answer 2

[N Narayan rao]

x = -3:0.1:3;
y1 = sin(x);
y2 = cos(x);
y3= tan(x);
y4=1./cos(x);

figure
subplot(2,2,1)      
plot(x,y1)          
title('Subplot 1')

subplot(2,2,2)       
plot(x,y2)        
title('Subplot 2')

subplot(2,2,3)      
plot(x,y3)          
title('Subplot 3')

subplot(2,2,4)       
plot(x,y4)
title('Subplot 4')

[AT]

How can we run many simulations at the same time? (for example for 1000 simulations)

or

How can we plot more than 100 graphs in one plot?

Answer 3

[Tom]

Thanks, that's perfect.

Answer 4

[Raghuram]

Could you please tell me the same with scatter plot command? That is, to plot multiple scatter plots in one figure?

[Prasad Kalane]

x=rand(2,10);
scatter(x(1,:),x(2,:),'r');
hold on
x=rand(2,10);
scatter(x(1,:),x(2,:),'g');
hold on
x=rand(2,10);
scatter(x(1,:),x(2,:),'b');
hold on
x=rand(2,10);
scatter(x(1,:),x(2,:),'c');

You can plot multiple plot just use "hold on" command

[MOHAMMAD YASIR ALI]

can I get best fit line from this method?

[Walter Roberson]

"can I get best fit line from this method?"

Best fit lines tend to imply an ordering to the data, but scatter plots tend to imply the data might not be ordered in a way that is compatible with fitting.

But yes, if you have polynomial coefficients for your fit, such as coefficients generated using polyfit(), then you can use polyval() to interpolate values, and you can "hold on" and plot() the values.

Answer 5

[Cortney Marschner]

How do I plot multiple graphs on the same graph using this code?:

hold off
[x, y] = meshgrid(0:0.2:10, 0:0.2:6);
X = x(1,1:51);
dx = ones(size(x));
dy = x;
quiver(x, y, dx, dy)
axis tight
hold on
plot(X, 1+X.^2/2)

[Walter Roberson]

That code already plots multiple lines on the same plot. However, the y range of the second one is much larger than the y range of the first, so the second one takes up most of the space.

Answer 6

[Emil Latypov]

In chemistry, the pH of an aqueous solution is a measure of its acidity. The pH scale ranges from 0 to 14, inclusive. A solution with a pH of 7 is said to be neutral, a solution with a pH greater than 7 is basic, and a solution with a pH less than 7 is acidic.

I did it, but my prof said it is not professional. How to do it professionally?

%% Chapter 8 Question 19
%% This script cteats the a vector structure mysol with various solutions  
%% and their pH-values and adds another field mysol.acidity.
clear
clc
format compact
mysol(3) = struct('name','bleach','pH',12);
mysol(1) = struct('name','juce','pH',5);
mysol(2) = struct('name','milk','pH',7);
acidity = myacidity(mysol);
for i = 1:3
  mysol(i).acidity = strcat(acidity(i,:));
end
mysol
mysol.acidity

function acidity = myacidity(mysol)
% This function receives a vector structure with various solutions and 
% their pH-values and determines acidity of solutions.
len = length(mysol);
acidity(len,:) = blanks(7);
  for i = 1:len
    if mysol(i).pH < 7
      acidity(i,:) = 'acidic ';
    elseif mysol(i).pH > 7
      acidity(i,:) = 'basic  ';
    else
      acidity(i,:) = 'neutral';
  end
end
end

[Image Analyst]

How is this an answer to Tom's question on "multiple plots on one graph"? I think you need to start your own question rather than post an answer to Tom's question.

[Walter Roberson]

The line

  mysol(i).acidity = strcat(acidity(i,:));

should probably be rewritten in terms of strtrim()

Answer 7

[Sankirna D. Joge]

One must use hold on command after every plot,

plot(x1,y1);
hold on
plot(x2,y2);
hold on
plot(x3,y3);
hold off

This will give output as three plots on a same graph.

[Walter Roberson]

This is not correct. "hold on" stays in effect until you turn it off (or the axes is cleared or deleted.)