matplotlib 如何在海运线图中使用自定义误差条

velaa5lx  于 11个月前  发布在  其他
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我正在使用seaborn.lineplot生成一些时间序列图。我已经在两个列表中预先计算了特定类型的误差线,例如upper=[1,2,3,4,5] lower=[0,1,2,3,4]。有没有一种方法可以在这里自定义误差线,而不是使用lineplot中的CI或Std误差线?

cgh8pdjw

cgh8pdjw1#

seaborn v0.12ci参数已更改为errorbar。在下面的示例中,使用errorbar='sd'而不是ci='sd'。还有errorbar=('sd', n),其中n是标准差的数量。
如果您需要seaborn.lineplot提供的误差带/条以外的误差带/条,你必须自己绘制它们。这里有几个例子,说明如何在matplotlib中绘制误差带和误差条,并获得与seaborn中类似的图。它们是用 fmri 构建的。示例数据集作为pandas框架导入,并基于lineplot function上的seaborn文档中显示的示例之一。

import numpy as np                 # v 1.19.2
import pandas as pd                # v 1.1.3
import matplotlib.pyplot as plt    # v 3.3.2
import seaborn as sns              # v 0.11.0

# Import dataset as a pandas dataframe
df = sns.load_dataset('fmri')

# display(df.head(3))
  subject  timepoint event    region    signal
0     s13         18  stim  parietal -0.017552
1      s5         14  stim  parietal -0.080883
2     s12         18  stim  parietal -0.081033

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这个数据集包含一个名为 timepoint 的时间变量,在19个时间点中的每个时间点上有56个 * 信号 * 的测量值。我使用默认的估计值,即平均值。为了简单起见,而不是使用平均值的标准误差的置信区间作为不确定性的度量(又名误差),我使用每个时间点测量的标准差。这是通过传递ci='sd'lineplot中设置的,误差扩展到平均值两侧的一个标准差(即对称)。以下是带有误差带的海运线图(默认情况下):

# Draw seaborn lineplot with error band based on the standard deviation
fig, ax = plt.subplots(figsize=(9,5))
sns.lineplot(data=df, x="timepoint", y="signal", ci='sd')
sns.despine()
plt.show()


x1c 0d1x的数据
现在假设我更喜欢在平均值两侧的每个时间点上设置一个误差带,该误差带跨越测量值的标准差的一半。由于在调用lineplot函数时无法设置此首选项,因此据我所知,最简单的解决方案是使用matplotlib从头开始创建图。

# Matplotlib plot with custom error band

# Define variables to plot
y_mean = df.groupby('timepoint').mean()['signal']
x = y_mean.index

# Compute upper and lower bounds using chosen uncertainty measure: here
# it is a fraction of the standard deviation of measurements at each
# time point based on the unbiased sample variance
y_std = df.groupby('timepoint').std()['signal']
error = 0.5*y_std
lower = y_mean - error
upper = y_mean + error

# Draw plot with error band and extra formatting to match seaborn style
fig, ax = plt.subplots(figsize=(9,5))
ax.plot(x, y_mean, label='signal mean')
ax.plot(x, lower, color='tab:blue', alpha=0.1)
ax.plot(x, upper, color='tab:blue', alpha=0.1)
ax.fill_between(x, lower, upper, alpha=0.2)
ax.set_xlabel('timepoint')
ax.set_ylabel('signal')
ax.spines['top'].set_visible(False)
ax.spines['right'].set_visible(False)
plt.show()



如果您更喜欢使用误差线,则海运线图如下所示:

# Draw seaborn lineplot with error bars based on the standard deviation
fig, ax = plt.subplots(figsize=(9,5))
sns.lineplot(data=df, x="timepoint", y="signal", ci='sd', err_style='bars')
sns.despine()
plt.show()



以下是如何使用自定义误差条使用matplotlib获得相同类型的图:

# Matplotlib plot with custom error bars

# If for some reason you only have lists of the lower and upper bounds
# and not a list of the errors for each point, this seaborn function can
# come in handy:
# error = sns.utils.ci_to_errsize((lower, upper), y_mean)

# Draw plot with error bars and extra formatting to match seaborn style
fig, ax = plt.subplots(figsize=(9,5))
ax.errorbar(x, y_mean, error, color='tab:blue', ecolor='tab:blue')
ax.set_xlabel('timepoint')
ax.set_ylabel('signal')
ax.spines['top'].set_visible(False)
ax.spines['right'].set_visible(False)
plt.show()

# Note: in this example, y_mean and error are stored as pandas series
# so the same plot can be obtained using this pandas plotting function:
# y_mean.plot(yerr=error)



Matplotlib文档:fill_betweenspecify error barssubsample error bars
Pandas文档:错误条

4ioopgfo

4ioopgfo2#

我可以通过在lineplot本身返回的轴上调用fill_between来实现这一点:

from seaborn import lineplot

ax = lineplot(data=dataset, x=dataset.index, y="mean", ci=None)
ax.fill_between(dataset.index, dataset.lower, dataset.upper, alpha=0.2)

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生成的图像:


的数据
作为参考,dataset是一个pandas.DataFrame,看起来像:

lower       mean      upper
timestamp                                           
2022-01-14 12:00:00  55.575585  62.264151  68.516173
2022-01-14 12:20:00  50.258980  57.368421  64.185814
2022-01-14 12:40:00  49.839738  55.162242  60.369063

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