Plot a Point or a Line on an Image with Matplotlib

Last Updated : 17 Dec, 2020

Prerequisites: Matplotlib

Matplotlib and its constituents support a lot of functionality. One such functionality is that we can draw a line or a point on an image using Matplotlib in python.

Approach

Import modules
Read the image
Plot the line or point on the image
Display the plot/image.

Image Used:

Implementation using the above approach on the given image is provided below:

Example 1 : Drawing a point on the image.

Attribute used: marker

It is used to define what marker type should the point be displayed in.

Python3

from matplotlib import image 
from matplotlib import pyplot as plt 
  
# to read the image stored in the working directory 
data = image.imread('sunset-1404452-640x480.jpg') 
  
# to draw a point on co-ordinate (200,300) 
plt.plot(200, 350, marker='v', color="white") 
plt.imshow(data) 
plt.show() 

Output:

Example 2 : Draw a line on the image

To draw a line we will give the co-ordinates of two points in the plot function.

Attribute used: linewidth

Used to specify the width of the line.

Python3

from matplotlib import image 
from matplotlib import pyplot as plt 
  
# to read the image stored in the working directory 
data = image.imread('sunset-1404452-640x480.jpg') 
  
# to draw a line from (200,300) to (500,100) 
x = [200, 500] 
y = [300, 100] 
plt.plot(x, y, color="white", linewidth=3) 
plt.imshow(data) 
plt.show() 

Output:

Example 3 : Draw two intersecting lines crossing each other to make X.

Python3

from matplotlib import image 
from matplotlib import pyplot as plt 
  
# to read the image stored in the working directory 
data = image.imread('sunset-1404452-640x480.jpg') 
  
# to draw first line from (100,400) to (500,100) 
# to draw second line from (150,100) to (450,400) 
x1 = [100, 500] 
y1 = [400, 100] 
x2 = [150, 450] 
y2 = [100, 400] 
plt.plot(x1, y1, x2, y2, color="white", linewidth=3) 
plt.axis('off') 
plt.imshow(data) 
plt.show() 