Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
Physics
Chemistry
Biology
Mathematics
English
Economics
Psychology
Social Studies
Fashion Studies
Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
How to customize the color and colormaps of a Plot in Matplotlib
To customize the color and colormaps of a plot, we can use the colormap property from the color library. There are two types of colormap we can create: (a) discrete colormap and (b) continuous colormap.
We will first see how to create a discrete colormap followed by continuous colormap.
In the example, we will use ‘iris’ dataset to create three plots such that the first plot uses the default colormap and the other two uses RGB map to create a mixed colored plot. However, we can create as many color maps as we have clusters.
Example
import matplotlib.pyplot as plt
import pandas as pd
import numpy as np
from matplotlib.colors import LinearSegmentedColormap
#Reading the iris dataset
iris = pd.read_csv('iris_dataset.csv', delimiter=',')
iris['species'] = iris['species'].map({"setosa" : 0, "versicolor" :1, "virginica" : 2})
#Defining the figure and its layout
fig, axs = plt.subplots(1,3, figsize=(9,6))
fig.subplots_adjust(left=0.0, bottom=0.05, right=0.9, top=0.95, wspace=0.6)
#Function to plot the graph
def plot_graph(axes, cm, cbaxs):
im = axes.scatter(iris.petal_length, iris.petal_width, s=10*iris.petal_length*iris.petal_width, c=iris.species, cmap = cm)
caxs = plt.axes(cbaxs)
fig.colorbar(im, caxs, ticks=range(3), label='clusetr #')
#Plot the iris dataset clusters with colors chosen from colormap
cbaxs = [0.24, 0.05, 0.03, 0.85] # left, bottom, width and height
plot_graph(axs[0], plt.cm.get_cmap('coolwarm', 3), cbaxs)
#Plot the iris dataset with custom colors RGB
colors = [(1, 0, 0), (0, 1, 0), (0, 0, 1)]
cm = LinearSegmentedColormap.from_list('custom_RGB_cmap', colors,N=3)
#Plot the iris dataset clusters with custom mixed colormaps
cbaxs = [0.58, 0.05, 0.03, 0.85]
plot_graph(axs[1], cm, cbaxs)
colors = [(1, 0.5, 0), (0.25, 0.5, 0.25), (0, 0.5, 1)]
cm = LinearSegmentedColormap.from_list('dummy', colors, N=3)
cbaxs = [0.95, 0.05, 0.03, 0.85]
plot_graph(axs[2], cm, cbaxs)
#Display the plot
plt.show()Output
Updated on: 23-Feb-2021
436 Views
Advertisements