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Matplotlib极坐标打印:以度为单位显示极坐标记号,采用十进制格式

polar-coordinates axis-labels plot matplotlib python

1

ascendants · 技术社区 · 7 年前

度 (例如,有两个小数位的浮点数),但这两种方法都不被明确支持。

或

但在我使用 ax.xaxis.set_major_formatter()

如何在指定十进制格式的同时强制执行度格式?

numpy.rad2deg )不起作用,因为 ax.set_xticks() 仅将参数解释为弧度(但是,Matplotlib在默认情况下将其显示为度…)

示例代码:

import numpy as np
import matplotlib.pyplot as plt

from matplotlib.ticker import FormatStrFormatter

minTheta = 0.42; maxTheta = 0.55

fig = plt.figure()
ax = fig.add_subplot(111, projection='polar')

#create four tick labels (in radians) dynamically based on the theta range
ticks = np.linspace(minTheta, maxTheta, 4)

ax.set_xticks(ticks)

#disable or enable the following line to change the tick display format*************
ax.xaxis.set_major_formatter(FormatStrFormatter('%.2f'))

#Adjust the sector window: you must call these AFTER setting the ticks, since setting the ticks
#actually adjusts the theta range window. This must be in degrees.
ax.set_thetamin(np.rad2deg(minTheta))
ax.set_thetamax(np.rad2deg(maxTheta))

2 回复 | 直到 7 年前

1

4

jtlz2 5 年前

极坐标图的内部单位是弧度。因此,记号的位置以弧度表示,这些是需要格式化的数字。您可以使用 FuncFormatter .

rad2fmt = lambda x,pos : f"{np.rad2deg(x):.2f}Â°"
ax.xaxis.set_major_formatter(FuncFormatter(rad2fmt))

完整的示例如下所示:

import numpy as np
import matplotlib.pyplot as plt

from matplotlib.ticker import FuncFormatter

minTheta = 0.42; maxTheta = 0.55

fig = plt.figure()
ax = fig.add_subplot(111, projection='polar')

#create four tick labels (in radians) dynamically based on the theta range
ticks = np.linspace(minTheta, maxTheta, 4)
ax.set_xticks(ticks)

#disable or enable the following line to change the tick display format*
rad2fmt = lambda x,pos : f"{np.rad2deg(x):.2f}Â°"
ax.xaxis.set_major_formatter(FuncFormatter(rad2fmt))

#Adjust the sector window: you must call these AFTER setting the ticks, since setting the ticks
#actually adjusts the theta range window. And it must be in degrees.
ax.set_thetamin(np.rad2deg(minTheta))
ax.set_thetamax(np.rad2deg(maxTheta))

plt.show()

2

1

Sheldore 7 年前

或者,你可以利用 PercentFormatter . 在这里 xmax np.pi*100/180 .

我通过一个注释来突出显示添加的三行代码 #

import numpy as np
import matplotlib.pyplot as plt
from matplotlib.ticker import PercentFormatter # <---


minTheta = 0.42; maxTheta = 0.55

fig = plt.figure()
ax = fig.add_subplot(111, projection='polar')

ticks = np.linspace(minTheta, maxTheta, 4)
ax.set_xticks(ticks)

ax.set_thetamin(np.rad2deg(minTheta))
ax.set_thetamax(np.rad2deg(maxTheta))

xmax = np.pi*100/180 # <---
ax.xaxis.set_major_formatter(PercentFormatter(xmax, decimals=2)) # <---