Plotting A 2D-Histogram Using Matplotlib


  • A 2D Histogram is very similar to the 1D Histogram.


  • In a 2D Histogram, class intervals are drawn in both X-axis and the Y-axis.


  • Unlike a 1D Histogram, 2D Histogram is plotted by counting the combination of values that occur in X and Y class intervals - and marking the densities.


  • A 2D Histogram is useful when there is lot of data in a bivariate distribution. 2D Histogram simplifies visualizing the areas where the frequency of variables is dense.


  • To plot a 2D histogram the length of X data and Y data should be equal.


  • Matplotlib provides hist2d() as part of the matplotlib.pyplot module which is used for plotting 2D Histograms.



import matplotlib.pyplot as plot

import numpy as np


# Data 1

x = (20, 30, 40, 50, 60, 70)

y = (10, 10, 10, 10, 10, 10)


# Plot frequency distribution using histogram

plot.hist2d(x, y)

plot.title("2D Histogram Construction")



# Display the histogram



By changing the data as the 2D-Histogram changes depicting the more number of 10s added in the x and y with increased density denoted by the yellow square, in the output below

New data is given by,

x = (20, 30, 40, 50, 60, 70,10,10,10)

y = (20, 10, 10, 10, 10, 10,10,10,10)

The color bar aids in decoding the density values.


Construction of 2D Histogram

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