How to change Matplotlib color bar size in Python?
Colorbar is a separate axis that provides a current colormap indicating mapping of data-points into colors. In this article, We are going to change Matplotlib color bar size in Python. There are several ways with which you can resize your color-bar or adjust its position. Let’s see it one by one.
Method 1: Resizing color-bar using shrink keyword argument
Using the shrink attribute of colorbar() function we can scale the size of the colorbar.
Syntax : matplotlib.pyplot.colorbar(mappable=None, shrink=scale)
Basically, we are multiplying by some factor to the original size of the color-bar. In the below example by using 0.5 as a factor, We are having the original color-bar size.
Example 1:
Python3
# importing library import matplotlib.pyplot as plt # Some data to show as an image data = [[1, 2, 3], [4, 5, 6]] # Call imshow() to display 2-D data as an image img = plt.imshow(data) # Scaling colorbar by factor 0.5 plt.colorbar(shrink=0.5) plt.show() |
Output:
Using_shrink_attribute
Example 2: In this example, we are using factor 0.75. Similarly, you can use any factor to change the color-bar size. The default value of the shrink attribute is 1.
Python3
import matplotlib.pyplot as plt import matplotlib.image as mpimg fig, ax = plt.subplots() # getting rid of axis plt.axis('off') # Reading saved image from folder img = mpimg.imread(r'img.jpg') # displaying image plt.imshow(img) # Scaling by factor 0.75 plt.colorbar(shrink=0.75) plt.show() |
Output:
Using_shrink_attribute
Method 2: Using AxesDivider class
With this class, you can change the size of the colorbar axes however height will be the same as the current axes. Here we are using axes_divider.make_axes_locatable function which returns the AxisDivider object for our current axes in which our image is shown.
Example:
Python3
# importing libraries import matplotlib.pyplot as plt from mpl_toolkits.axes_grid1 import make_axes_locatable fig, ax = plt.subplots() # Reading image from folder img = mpimg.imread(r'img.jpg') image = plt.imshow(img) # Locating current axes divider = make_axes_locatable(ax) # creating new axes on the right # side of current axes(ax). # The width of cax will be 5% of ax # and the padding between cax and ax # will be fixed at 0.05 inch. colorbar_axes = divider.append_axes("right", size="10%", pad=0.1) # Using new axes for colorbar plt.colorbar(image, cax=colorbar_axes) plt.show() |
Output:
Using_AxisDivider
