Matplotlib颜色条移动第二个X轴 [英] Matplotlib colorbar moves second x axis

问题描述

我正在尝试使用

如果我添加一个颜色条，则x轴的顶部会移位:

我该如何解决?

<小时>

MWE

将 numpy 导入为 np导入matplotlib.pyplot作为plt从 mpl_toolkits.axes_grid1 导入 make_axes_locatable导入 matplotlib.gridspec 作为 gridspecX = np.array([0., 0.5, 1., 1.5, 2., 2.5, 3., 3.5, 4.])X2 = np.array([122, 85, 63, 50, 23, 12, 7, 5, 2])Y = np.cos(X * 20)Z = np.sin(X*20)无花果= plt.figure()gs = gridspec.GridSpec(1、2)ax1 = plt.subplot(gs [1])ax2 = ax1.twiny()ax1.set_xlim(-0.2, max(X)+0.2)plt.tick_params(axis ='both'，which ='major'，labelsize = 10)ax1.minorticks_on()ax1.grid(b=True, which='major', color='gray', linestyle='--', lw=0.3)SC = ax1.scatter(X，Y，c = Z)ax1.set_xlabel(原始x轴")ax2.set_xlim(ax1.get_xlim())ax2.set_xticks(X)ax2.set_xticklabels(X2)ax2.set_xlabel("第二个x轴")#彩条.the_divider = make_axes_locatable(ax1)color_axis = the_divider.append_axes("right", size="2%", pad=0.1)cbar = plt.colorbar(SC，cax = color_axis)cbar.set_label('B'，fontsize = 10，labelpad = 4，y = 0.5)cbar.ax.tick_params(labelsize=10)plt.show()

解决方案

您可以在

如果你需要使用 tight_layout 这样的东西(这需要对填充等进行一些调整):

将 numpy 导入为 np导入matplotlib.pyplot作为plt导入 matplotlib.gridspec 作为 gridspecX = np.array([0.，0.5，1.，1.5，2.，2.5，3.，3.5，4.])X2 = np.array([122，85，63，50，23，12，7，5，5，2])Y = np.cos(X*20)Z = np.sin(X*20)无花果= plt.figure()gs = gridspec.GridSpec(1、2)right_gs = gridspec.GridSpecFromSubplotSpec(1、2，width_ratios = [30、1]，subplot_spec = gs [1]，wspace = 0.05)ax1 = fig.add_subplot(right_gs[0])color_axis = fig.add_subplot(right_gs [1])ax2 = ax1.twiny()ax1.set_xlim(-0.2，max(X)+0.2)plt.tick_params(axis='both', which='major', labelsize=10)ax1.minorticks_on()ax1.grid(b=True, which='major', color='gray', linestyle='--', lw=0.3)SC = ax1.scatter(X, Y, c=Z, cmap='viridis')ax1.set_xlabel(原始x轴")ax2.set_xlim(ax1.get_xlim())ax2.set_xticks(X)ax2.set_xticklabels(X2)ax2.set_xlabel("第二个x轴")cbar = fig.colorbar(SC，cax = color_axis)cbar.set_label('B'，fontsize = 10，labelpad = 4，y = 0.5)cbar.ax.tick_params(labelsize=10)fig.tight_layout()plt.show()

I'm trying to add a second x axis to the top of a plot using twiny.

If I make a simple scatter plot with no colorbar, the top x axis is correctly aligned with the bottom x axis (MWE is below):

If I add a colorbar though, the top x axis is displaced:

How can I fix this?

---

MWE

import numpy as np
import matplotlib.pyplot as plt
from mpl_toolkits.axes_grid1 import make_axes_locatable
import matplotlib.gridspec as gridspec


X = np.array([0., 0.5, 1., 1.5, 2., 2.5, 3., 3.5, 4.])
X2 = np.array([122, 85, 63, 50, 23, 12, 7, 5, 2])
Y = np.cos(X*20)
Z = np.sin(X*20)

fig = plt.figure()
gs = gridspec.GridSpec(1, 2)
ax1 = plt.subplot(gs[1])
ax2 = ax1.twiny()

ax1.set_xlim(-0.2, max(X)+0.2)
plt.tick_params(axis='both', which='major', labelsize=10)
ax1.minorticks_on()
ax1.grid(b=True, which='major', color='gray', linestyle='--', lw=0.3)

SC = ax1.scatter(X, Y, c=Z)
ax1.set_xlabel("Original x-axis")

ax2.set_xlim(ax1.get_xlim())
ax2.set_xticks(X)
ax2.set_xticklabels(X2)
ax2.set_xlabel("Second x-axis")

# Colorbar.
the_divider = make_axes_locatable(ax1)
color_axis = the_divider.append_axes("right", size="2%", pad=0.1)
cbar = plt.colorbar(SC, cax=color_axis)
cbar.set_label('B', fontsize=10, labelpad=4, y=0.5)
cbar.ax.tick_params(labelsize=10)

plt.show()

解决方案

You can have the colorbar 'steal' space from more than one ax

import numpy as np
import matplotlib.pyplot as plt
from mpl_toolkits.axes_grid1 import make_axes_locatable
import matplotlib.gridspec as gridspec

X = np.array([0., 0.5, 1., 1.5, 2., 2.5, 3., 3.5, 4.])
X2 = np.array([122, 85, 63, 50, 23, 12, 7, 5, 2])
Y = np.cos(X*20)
Z = np.sin(X*20)

fig = plt.figure()
gs = gridspec.GridSpec(1, 2)
ax1 = plt.subplot(gs[1])
ax2 = ax1.twiny()

ax1.set_xlim(-0.2, max(X)+0.2)
plt.tick_params(axis='both', which='major', labelsize=10)
ax1.minorticks_on()
ax1.grid(b=True, which='major', color='gray', linestyle='--', lw=0.3)

SC = ax1.scatter(X, Y, c=Z, cmap='viridis')
ax1.set_xlabel("Original x-axis")

ax2.set_xlim(ax1.get_xlim())
ax2.set_xticks(X)
ax2.set_xticklabels(X2)
ax2.set_xlabel("Second x-axis")

# Colorbar.
cbar = plt.colorbar(SC, ax=[ax1, ax2])
cbar.set_label('B', fontsize=10, labelpad=4, y=0.5)
cbar.ax.tick_params(labelsize=10)

plt.show()

which I think will un-block your use case.

Limits are a bit different because I am sitting on the current master branch.

If you need to use tight_layout something like this (which requires some tuning on padding etc):

import numpy as np
import matplotlib.pyplot as plt
import matplotlib.gridspec as gridspec


X = np.array([0., 0.5, 1., 1.5, 2., 2.5, 3., 3.5, 4.])
X2 = np.array([122, 85, 63, 50, 23, 12, 7, 5, 2])
Y = np.cos(X*20)
Z = np.sin(X*20)

fig = plt.figure()
gs = gridspec.GridSpec(1, 2)
right_gs = gridspec.GridSpecFromSubplotSpec(1, 2, width_ratios=[30, 1], subplot_spec=gs[1], wspace=0.05)

ax1 = fig.add_subplot(right_gs[0])
color_axis = fig.add_subplot(right_gs[1])



ax2 = ax1.twiny()

ax1.set_xlim(-0.2, max(X)+0.2)
plt.tick_params(axis='both', which='major', labelsize=10)
ax1.minorticks_on()
ax1.grid(b=True, which='major', color='gray', linestyle='--', lw=0.3)

SC = ax1.scatter(X, Y, c=Z, cmap='viridis')
ax1.set_xlabel("Original x-axis")

ax2.set_xlim(ax1.get_xlim())
ax2.set_xticks(X)
ax2.set_xticklabels(X2)
ax2.set_xlabel("Second x-axis")

cbar = fig.colorbar(SC, cax=color_axis)
cbar.set_label('B', fontsize=10, labelpad=4, y=0.5)
cbar.ax.tick_params(labelsize=10)

fig.tight_layout()
plt.show()

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