【python图像处理】python绘制极坐标图

极坐标图在数据统计和分析中也经常会用到，这里就介绍一下如何使用python来绘制极坐标图，主要介绍极坐标散点图和极坐标饼状图。

1、极坐标散点图

N = 150
r = 2 * np.random.rand(N)
theta = 2 * np.pi * np.random.rand(N)
area = 200 * r**2
colors = theta

ax = plt.subplot(111, projection='polar')
c = ax.scatter(theta, r, c=colors, s=area, cmap='hsv', alpha=0.75)

plt.show()

绘制结果如下：

2、极坐标饼状图

import numpy as np
import matplotlib.pyplot as plt


# Compute pie slices
N = 20
theta = np.linspace(0.0, 2 * np.pi, N, endpoint=False)
radii = 10 * np.random.rand(N)
width = np.pi / 4 * np.random.rand(N)

ax = plt.subplot(111, projection='polar')
bars = ax.bar(theta, radii, width=width, bottom=0.0)

# Use custom colors and opacity
for r, bar in zip(radii, bars):
    bar.set_facecolor(plt.cm.viridis(r / 10.))
    bar.set_alpha(0.5)

plt.show()

绘制结果如下：

2017.09.21