Pie Chart in MATLAB

A Pie chart is a circular graph that is divided into sections and each section represents the proportionate part of the whole. In MATLAB we have a function named pie() which allows us to plot a bar graph. 

Syntax:

pie(X)

pie(X) draws a pie chart using the data in X. Each slice of the pie chart represents an element in X.

• Where the sum(X) ≤ 1, then the areas of the pie slices directly specify the values in X pie draws only a partial pie if sum(X) < 1.
• Where the sum(X) > 1, then the area of each slice of the pie is determined by pie normalizes the values by X/sum(X)
• Here let X be a categorical data type, the slices correspond to categories. The number of elements in the category divided by the number of elements in X becomes The area of each slice.

Now let's move to some examples.

Example 1: A simple pie chart:

MATLAB

% data 
b= [20 30 40 30]

% pie function to draw pie chart
pie(b)

Output :

fig 1: Pie chart

Example 2: Pie chart with offset:

MATLAB

% data
b= [20 30 40 30]
% offset first and third by using 1 at explode 
explode = [1 0 1 0]

% pie function to draw pie chart with
% explode 1st and 3rd position data
pie(b,explode)

Output :

fig 2: Pie chart with offset

Example 3: Pie chart with labels:

MATLAB

% data
b= [20 30 40 30]

% labelling on Pie chart
labels={'a','b','c','d'}

% pie function to draw pie chart with labels
pie(b,labels)

Output :

fig 3: Pie chart with labels

Example 4: Partial Pie chart:

MATLAB

% create vector whose sum is less than 1
b= [0.2 0.4 0.1]

% pie function to draw pie chart
pie(b)

Output :

fig 4: Partial Pie chart

Example 5: Compare 2 pie charts:

MATLAB

% data
b= [20 30 40 30]
a= [10 40 20 20]

% labelling on pie chart
labels={'a','b','c','d'}

% to add more than 1 plot in same figure
t = tiledlayout(1,2,'TileSpacing','compact');

% create pie charts
ax1 = nexttile;
pie(ax1,a)
title('Pie chart 1')
ax2 = nexttile;
pie(ax2,b)
title('Pie chart 2')

% create legend and put labels as arguments
lgd = legend(labels);
% position of legend there are 4 positions
%'north','south','east','west'
lgd.Layout.Tile = 'north';

Output : 

fig 5: Comparison of 2 pie charts

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