How to plot a pcolor colorbar in a different subplot in Matplotlib?

To plot a pcolor colorbar in a different subplot in Matplotlib, you can create multiple subplots and add individual colorbars to each one using the fig.colorbar() method.

Basic Setup

First, let's understand the key components needed ?

• Create a figure with multiple subplots using plt.subplots()
• Generate pseudocolor plots with pcolormesh()
• Add colorbars using fig.colorbar() with specific axis references
• Use different colormaps for visual distinction

Example: Multiple Subplots with Individual Colorbars

import matplotlib.pyplot as plt
import numpy as np

# Set figure size
plt.rcParams["figure.figsize"] = [10, 6]
plt.rcParams["figure.autolayout"] = True

# Create 2x2 subplot grid
fig, axs = plt.subplots(2, 2)

# Define different colormaps
colormaps = ['plasma', 'copper']

# Create pcolor plots with colorbars
for col in range(2):
    for row in range(2):
        ax = axs[row, col]
        
        # Generate random data scaled by column
        data = np.random.random((20, 20)) * (col + 1)
        
        # Create pcolormesh plot
        pcm = ax.pcolormesh(data, cmap=colormaps[col])
        
        # Add colorbar to current subplot
        fig.colorbar(pcm, ax=ax)
        
        # Set subplot title
        ax.set_title(f'Subplot ({row+1}, {col+1}) - {colormaps[col]}')

plt.tight_layout()
plt.show()

Alternative: Shared Colorbar Across Subplots

You can also create a single colorbar that applies to multiple subplots ?

import matplotlib.pyplot as plt
import numpy as np

# Create figure and subplots
fig, (ax1, ax2) = plt.subplots(1, 2, figsize=(10, 4))

# Generate sample data
data1 = np.random.random((15, 15)) * 10
data2 = np.random.random((15, 15)) * 10

# Create pcolormesh plots with same colormap
pcm1 = ax1.pcolormesh(data1, cmap='viridis', vmin=0, vmax=10)
pcm2 = ax2.pcolormesh(data2, cmap='viridis', vmin=0, vmax=10)

# Add titles
ax1.set_title('Dataset 1')
ax2.set_title('Dataset 2')

# Create shared colorbar
fig.colorbar(pcm1, ax=[ax1, ax2], shrink=0.8, location='bottom')

plt.tight_layout()
plt.show()

Key Parameters

Conclusion

Use fig.colorbar(pcm, ax=ax) to add individual colorbars to specific subplots. For shared colorbars across multiple subplots, pass a list of axes to the ax parameter.