Overlaying a Bar chart with 2 Y-axes and 2 legends. My code below plots data x and y versus xx. I want the right Y-axes to have the amplitudes of data "y". And also I will like a legend for data "x" on the top right corner. Any suggestions?

y= [1.5 5.5 2.46 1.36; 6.5 44.35 3.46 16; 9.5 99 50 2.33;17.76 39.38 12.7 2.0;...
    20 35 16.18 2.35];
x=[17 19 3 3;70 66 22 25;65 225 42 16; 75 292 32 16; 132 205 29 18];

xx=[1 2 3 4 5];

w1 = .7;

h(:,1)=bar(xx,y,w1,'FaceColor','flat');
legend(h(:,1), {'Imaging','Mechanical','Cyclotron','Software'},'Location','northeast');

grid on

hold on

w2=0.4;

h(:,2)=bar(xx,x,w2,'FaceColor','flat');

set(gca,'XTickLabel',{'Sep-Dec, 2014','2015','2016','2017','2018'});
legend(h(:,2), {'Imaging','Mechanical','Cyclotron','Software'},'Location','northwest');


hold off

Answer 1

[Vedant Shah]

Hi @Percy N,

After generating both plots, we can add the legends with proper titles. Additionally, we need to hide the visibility of the extra axes to ensure that both legends are visible. The dual axes will be displayed using the “yyaxis” function. For further information, please refer to the following documentation:

web(fullfile(docroot, "/matlab/ref/axes.html")) 
web(fullfile(docroot, "/matlab/ref/legend.html")) 
web(fullfile(docroot, "/matlab/ref/yyaxis.html")) 

Below is the code that accomplishes the desired functionality:

% Data for bar charts 
y = [1.5 5.5 2.46 1.36; 6.5 44.35 3.46 16; 9.5 99 50 2.33; 17.76 39.38 12.7 2.0; 20 35 16.18 2.35]; 
x = [17 19 3 3; 70 66 22 25; 65 225 42 16; 75 292 32 16; 132 205 29 18]; 
xx = [1 2 3 4 5]; 
w1 = 0.7; 
w2 = 0.4; 

% Create figure 
figure; 

% Create bar chart for y data 
yyaxis left 
h1 = bar(xx, y, w1, 'FaceColor', 'flat'); 
ylabel('Y Data') 

% Set different colors for y data bars 
colors_y = [0.8 0.2 0.2; 0.2 0.8 0.2; 0.2 0.2 0.8; 0.8 0.8 0.2]; 
for k = 1:size(y, 2) 
    h1(k).CData = colors_y(k, :); 
end 


% Overlay bar chart for x data on the right Y-axis 
yyaxis right 
h2 = bar(xx, x, w2, 'FaceColor', 'flat'); 
ylabel('X Data') 

% Set different colors for x data bars 
colors_x = [0.5 0.5 0.5; 0.3 0.3 0.3; 0.7 0.7 0.7; 0.4 0.4 0.4]; 
for k = 1:size(x, 2) 
    h2(k).CData = colors_x(k, :); 
end 

l1 = legend(h1, {'Imaging', 'Mechanical', 'Cyclotron', 'Software'}); 
title(l1, 'Y Data'); 
ah1=axes('position',get(gca,'position'),'visible','off'); 
l2 = legend(ah1,h2, {'Imaging_2', 'Mechanical', 'Cyclotron', 'Software'},'Location','NorthWest'); 
title(l2, 'X Data'); 

% Set x-axis labels 
set(gca, 'XTickLabel', {'Sep-Dec, 2014', '2015', '2016', '2017', '2018'}); 

% Enable grid 
grid on 

In this code, I have also applied distinct colors to each of the bars to enhance differentiation and visualization.

The output generated by this code is as follows: