How do I place errorbars on my grouped bar graph using function ERRORBAR in MATLAB?

I use the following to create a grouped bar graph:

model_series = [10 40 50 60; 20 50 60 70; 30 60 80 90];
model_error = [1 4 8 6; 2 5 9 12; 3 6 10 13];
bar(model_series, 'grouped');
hold on
errorbar( model_series,model_error)

The result is a grouped bar graph with error bars placed in between each group of bars:

I would like to have "errorbar" place error bars on the center of each bar.

Answer 1

[MathWorks Support Team]

The ability to specify that the "errorbar" function should display the error bars inside the patches is not available in MATLAB.

There are two work arounds for this limitation, usage of which depends on the release of MATLAB that you are using.

For R2019a or earlier releases:

Find the center of each bar and pass this data into "errorbar" with the respective error values.

% Example data 
model_series = [10 40 50 60; 20 50 60 70; 30 60 80 90];
model_error = [1 4 8 6; 2 5 9 12; 3 6 10 13];
b = bar(model_series, 'grouped');

hold on
% Find the number of groups and the number of bars in each group
[ngroups, nbars] = size(model_series);

% Calculate the width for each bar group
groupwidth = min(0.8, nbars/(nbars + 1.5));

% Set the position of each error bar in the centre of the main bar
% Based on barweb.m by Bolu Ajiboye from MATLAB File Exchange
for i = 1:nbars
    % Calculate center of each bar
    x = (1:ngroups) - groupwidth/2 + (2*i-1) * groupwidth / (2*nbars);
    errorbar(x, model_series(:,i), model_error(:,i), 'k', 'linestyle', 'none');
end
hold off

For R2019b or later releases:

Retrieve the x coordinate of each bar using the "XEndPoints" property and pass this data into "errorbar":

https://www.mathworks.com/help/releases/R2019b/matlab/ref/matlab.graphics.chart.primitive.bar-properties.html#mw_3d0c5b61-b082-4c79-b9c6-a21152ae26ff

% Example data 
model_series = [10 40 50 60; 20 50 60 70; 30 60 80 90]; 
model_error = [1 4 8 6; 2 5 9 12; 3 6 10 13]; 
b = bar(model_series, 'grouped');

hold on
% Calculate the number of groups and number of bars in each group
[ngroups,nbars] = size(model_series);

% Get the x coordinate of the bars
x = nan(nbars, ngroups);
for i = 1:nbars
    x(i,:) = b(i).XEndPoints;
end

% Plot the errorbars
errorbar(x',model_series,model_error,'k','linestyle','none');
hold off

 

[Oleg Komarov]

TK1234 answered with "You are brilliant". I moved his answer to the comment section here.

[Michael Abboud]

Hi Miraflor, this answer has been recently updated.

If the above method still results in uncentered error bars, I would suggest you look primarily at the 3rd-to-last line where the locations are calculated, or contact MathWorks Technical Support for further assistance.