Adjust one subplot's height in absolute way (not relative) in Matplotlib

When creating subplots in Matplotlib, you sometimes need precise control over their positioning and dimensions. The Axes() class allows you to specify absolute positions and sizes instead of using relative grid layouts.

Understanding Axes Parameters

The Axes() class takes parameters [left, bottom, width, height] where all values are in figure coordinates (0 to 1) ?

• left − horizontal position of the left edge
• bottom − vertical position of the bottom edge
• width − width of the subplot
• height − height of the subplot

Example

Here's how to create two subplots with different absolute heights ?

import matplotlib.pyplot as plt

plt.rcParams["figure.figsize"] = [7.50, 4.50]
plt.rcParams["figure.autolayout"] = True

figure = plt.figure()

# First subplot: positioned at [0.4, 0.6] with size [0.25, 0.25]
axes1 = plt.Axes(figure, [0.4, 0.6, 0.25, 0.25])
figure.add_axes(axes1)
plt.plot([1, 2, 3, 4], [1, 2, 3, 4])

# Second subplot: positioned at [0.4, 0.1] with size [0.25, 0.25]  
axes2 = plt.Axes(figure, [0.4, 0.1, 0.25, 0.25])
figure.add_axes(axes2)
plt.plot([1, 2, 3, 4], [1, 2, 3, 4])

plt.show()

Creating Subplots with Different Heights

To demonstrate absolute height control, let's create subplots with different heights ?

import matplotlib.pyplot as plt

fig = plt.figure(figsize=(8, 6))

# Tall subplot on the left
tall_axes = plt.Axes(fig, [0.1, 0.1, 0.3, 0.8])  # height = 0.8
fig.add_axes(tall_axes)
tall_axes.plot([1, 2, 3], [1, 4, 2], 'b-', linewidth=2)
tall_axes.set_title('Tall Subplot')

# Short subplot on the right  
short_axes = plt.Axes(fig, [0.6, 0.3, 0.3, 0.4])  # height = 0.4
fig.add_axes(short_axes)
short_axes.plot([1, 2, 3], [3, 1, 4], 'r-', linewidth=2)
short_axes.set_title('Short Subplot')

plt.show()

Comparison with subplot()

Conclusion

Use plt.Axes() with [left, bottom, width, height] parameters for absolute control over subplot positioning and dimensions. This method provides precise layout control when standard grid layouts aren't sufficient.