How to adjust the (absolute) width of bars to 1 unit in a bar plot?

How to adjust the (absolute) width of bars to 1 unit in a bar plot?

In the following example, the bars are larger than 1 unit:

clear all;clc;close all;
a=[2 6 15 63];
b=[23 4 2 1];
bar(a,b,'FaceColor',[0.5 0.5 0.5],'FaceAlpha',0.2)
xlim([0 Inf])

I mean, even though we set the relative bar width (bar(___,width)) equal to 1, we do not get 1 unit large columns. I guess because we are talking about the relative bar width and not about the absolute bar width.

bar(a,b,1,'FaceColor',[0.5 0.5 0.5],'FaceAlpha',0.2)
xlim([0 Inf])

For example, I would expect that the column centered at tick 2 spans between 1.5 and 2.5.

[Dyuman Joshi]

How do you define '1 unit'?

[Sim]

Hi @Dyuman Joshi, I would define it as "I would expect that the column centered at tick 2 spans between 1.5 and 2.5, i.e. 1 unit ".

[Mann Baidi]

Hi Sim,

Here is a possible workaround.

clear all;clc;close all;
a=[2 6 15 63];
b=[23 4 2 1];

r=1:63;
s=zeros(1,63);
s(a)=b;
x=bar(r,s,'FaceColor',[0.5 0.5 0.5],'FaceAlpha',0.2);
x.BarWidth= 1;
xticks(a)

If you zoom this graph after running in the Desktop app. You will be able to get your desired result

[Sim]

Hi @Mann Baidi, thanks a lot for your idea! I am testing both yours and @Dyuman Joshi solutions. About your solution, I have noticed that for another set of inputs, the bars do not have the edge anymore...and I do not the reason why..

a = [8     9    12    13    14    15    16    22    46    81   178];
b = [3     1     1     1     3    24     2     1     1     1     1];
r=1:a(end);
s=zeros(1,a(end));
s(a)=b;
x=bar(r,s,'FaceColor',[0.5 0.5 0.5],'FaceAlpha',0.2);
x.BarWidth= 1;
xticks(a)

[Mann Baidi]

Update the EdgeColor by

x.EdgeColor=[1 1 1]; % for white edges [0 0 0] for black edges

[Sim]

great, thanks a lot! :-)

Answer 1

[Dyuman Joshi]

"I would expect that the column centered at tick 2 spans between 1.5 and 2.5, i.e. 1 unit "

That will be quarter of the width available for a bar -

%Modified values to get a better visual
a=[2 6 15];
b=[23 4 2];
bar(a,b,0.25,'FaceColor',[0.5 0.5 0.5],'FaceAlpha',0.2)
xlim([0 Inf])

vec = [a-0.5;a;a+0.5];
%Adding ticks for visual verification
xticks(vec(:))
ax=gca;
ax.FontSize = 9;
ax.XTickLabelRotation = 90;

[Sim]

Many thanks @Dyuman Joshi! I was testing your solution with different input values, and I got an error... :-)

% a=[2 6 15];
% b=[23 4 2];
a = [8     9    12    13    14    15    16    22    46    81   178];
b = [3     1     1     1     3    24     2     1     1     1     1];
bar(a,b,0.25,'FaceColor',[0.5 0.5 0.5],'FaceAlpha',0.2)
xlim([0 Inf])

vec = [a-0.5;a;a+0.5];
%Adding ticks for visual verification
xticks(vec(:))

Error using xticks
Value must be a numeric vector whose values increase.

ax=gca;
ax.FontSize = 9;
ax.XTickLabelRotation = 90;

[Dyuman Joshi]

xticks() requires the data to be non-repeating (and increasing).

However, with different data, the total available width for bars will change as well, so you will have to adjust the relative width accordingly.

I suppose you want a general solution for this?

% a=[2 6 15];
% b=[23 4 2];
a = [8     9    12    13    14    15    16];
b = [3     1     1     1     3    24     2];
bar(a,b,0.25,'FaceColor',[0.5 0.5 0.5],'FaceAlpha',0.2)

xlim([0 Inf])

vec = [a-0.5;a;a+0.5];
%Adding ticks for visual verification
xticks(unique(vec))
ax=gca;
ax.FontSize = 9;
ax.XTickLabelRotation = 90;

figure
bar(a,b,1,'FaceColor',[0.5 0.5 0.5],'FaceAlpha',0.2)
xticks(unique(vec))
ax=gca;
ax.FontSize = 9;
ax.XTickLabelRotation = 90;

[Sim]

Thanks a lot @Dyuman Joshi for your comments! Yes, I would like to have a general solution..... I guess it would be the following one, right?

bar(a,b,1,'FaceColor',[0.5 0.5 0.5],'FaceAlpha',0.2)
xticks(unique(vec))

[Sim]

@Mann Baidi and @Dyuman Joshi, many thanks for your solutions, which are both nice :-)