Understanding Quiver Plot

In this tutorial, we will cover the Quiver Plot using Matplotlib Library.

To plot the 2D field of arrows, we use the Quiver plot in the matplotlib library.

• This plot mainly helps in displaying the velocity vectors as arrows having components **(u,v)** at the points **(x,y)**.
• The Quiver plots are useful for Electrical engineers to visualize electrical potential and for Mechanical engineers to show stress gradients.

In order to create a Quiver Plot the ax.quiver() function is used.

The required syntax to use this function is as follows:

ax.quiver(x_pos, y_pos, x_dir, y_dir, color) 

Following are the parameters of this function, which you can see above in the syntax:

• x_pos and y_pos

  These two parameters of the function are used to indicate the starting position of the arrows.

• x_dir and y_dir

  These two parameters of the function are used to indicate the directions of the arrows.

• color

  This parameter is used to specify the color of the Quiver Plot.

Let us now dive into some examples related to this.

In the example given below, we will cover how to plot a Quiver plot with a single arrow:

import numpy as np 
import matplotlib.pyplot as plt 

x_pos = 0
y_pos = 0
x_direct = 1
y_direct = 1

fig, ax = plt.subplots(figsize = (10, 7)) 
ax.quiver(x_pos, y_pos, x_direct, y_direct) 
ax.set_title('Quiver plot with a single arrow') 

plt.show() 

Here is the output:

In the example given below, we will cover how to plot a Quiver plot with two arrows:

import numpy as np 
import matplotlib.pyplot as plt 

x_pos = [0, 0] 
y_pos = [0, 0] 
x_direct = [1, 0] 
y_direct = [1, -1] 

fig, ax = plt.subplots(figsize = (12, 7)) 
ax.quiver(x_pos, y_pos, x_direct, y_direct,scale = 8) 

ax.axis([-1.5, 1.5, -1.5, 1.5]) 

plt.show() 

Here is the output: