Scatter plot: Decreasing spacing between scatter points/x-axis t

ghz 13hours ago ⋅ 2 views

Scatter plot: Decreasing spacing between scatter points/x-axis ticks

I am currently working on a 2x2 subplot figure. In each subplot, I have 3 groups on the X axis. I want to decrease the spacing between each of these groups on the X-axis. Currently, the last value on 221 subplot is very close to the first value of 222 subplot.

I have changed the spacing between subplots but I would like each of the subplots to be more compact by decreasing the spacing between the X-axis values. The variable on the X-axis is non-numeric.

Answer

To decrease the spacing between the groups on the X-axis in your 2x2 subplot figure, especially when your variable on the X-axis is non-numeric, you can adjust the xticks or the width of each group, and fine-tune the padding and spacing settings in matplotlib.

Key Strategies to Decrease the Spacing Between Groups:

  1. Adjust the width of each bar (or data point) in the X-axis: If you're using bar plots or any categorical plots, decreasing the bar width will reduce the spacing between the categories on the X-axis.

  2. Control the tight_layout or subplots_adjust: If you want more compact spacing between subplots, you can adjust the layout with plt.subplots_adjust or fig.tight_layout(). However, if the issue is specifically between categories (rather than subplots), you'll need to adjust the tick positions and spacing.

  3. Manually adjust xticks positions: You can manually set the positions of the ticks or slightly shift them to reduce space between the groups.

Example Code

Here's an example of how to adjust both the width of each group and the spacing between the X-ticks in a 2x2 subplot setup:

import matplotlib.pyplot as plt
import numpy as np

# Create some example data
x_labels = ['Group 1', 'Group 2', 'Group 3']
y_values_1 = [10, 20, 30]
y_values_2 = [15, 25, 35]

# Create 2x2 subplot figure
fig, axs = plt.subplots(2, 2, figsize=(10, 8))

# Adjust the spacing between the subplots (but this is not related to X-axis spacing)
plt.subplots_adjust(hspace=0.4, wspace=0.4)

# First subplot (221)
axs[0, 0].bar(x_labels, y_values_1, width=0.6)  # Reduce width for more compact spacing
axs[0, 0].set_title('Plot 1')

# Second subplot (222)
axs[0, 1].bar(x_labels, y_values_2, width=0.6)
axs[0, 1].set_title('Plot 2')

# Third subplot (223)
axs[1, 0].bar(x_labels, y_values_1, width=0.6)
axs[1, 0].set_title('Plot 3')

# Fourth subplot (224)
axs[1, 1].bar(x_labels, y_values_2, width=0.6)
axs[1, 1].set_title('Plot 4')

# Fine-tune the spacing between ticks
for ax in axs.flat:
    ax.set_xticks(np.arange(len(x_labels)))
    ax.set_xticklabels(x_labels, rotation=45, ha='right')  # Adjust rotation for clarity

# Display the figure
plt.tight_layout()
plt.show()

Explanation:

  1. width=0.6 in bar():

    • The width parameter controls the width of each bar. By reducing it (e.g., to 0.6 instead of the default 0.8), you decrease the space between bars for each group. You can adjust this width to find the optimal spacing that fits your needs.

  2. Adjusting the spacing between subplots:

    • plt.subplots_adjust(hspace=0.4, wspace=0.4) adjusts the vertical (hspace) and horizontal (wspace) spacing between subplots. This will ensure that there is space between your subplots, but without making them too far apart.

  3. ax.set_xticks and ax.set_xticklabels:

    • We set the xticks manually using np.arange(len(x_labels)) to ensure the ticks are positioned correctly.
    • The xticklabels are set with a rotation of 45 degrees for better readability, especially if the labels are long or non-numeric.
    • The ha='right' option ensures the labels are aligned to the right for better spacing.

  4. Using plt.tight_layout():

    • This adjusts the layout of the entire figure automatically to ensure that subplots do not overlap. It will adjust the spacing around the subplots (including between the X-axis ticks and labels).

Customizing Spacing:

You can further fine-tune the spacing between the X-ticks if necessary using ax.margins(x=...), which will add padding around the X-axis. This will help you control the exact placement of the ticks within each subplot.

for ax in axs.flat:
    ax.margins(x=0.05)  # Adds margin to X-axis (e.g., 5% on each side)

This approach should allow you to make each subplot more compact and adjust the space between groups on the X-axis without affecting the spacing between subplots.

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