matplotlib之设置极坐标起点的位置

 #!/usr/bin/env python3
 #-*- coding:utf-8 -*-
 ############################
 #File Name: polar.py
 #Author: frank
 #Mail: frank0903@aliyun.com
 #Created Time:2018-05-22 22:08:01
 ############################
 import matplotlib.pyplot as plt
 import numpy as np
 import matplotlib as mpl

 zhfont = mpl.font_manager.FontProperties(fname='/usr/share/fonts/truetype/wqy/wqy-microhei.ttc')#载入中文字符库，否则会显示乱码

 plt.subplots_adjust(wspace=0.3)#控制两个subplot的间距，否则会有部分标签重叠
 ax1 = plt.subplot(121, polar=True)
 ax2 = plt.subplot(122, polar=True)

 #ax2.set_theta_zero_location("N")　　　#将起点位置设为 北部
 ax2.set_theta_zero_location("N", 30.0)#将起点位置设为 北部 偏移30度的位置，偏移的方向总是逆时针方向，无论theta direction的顺时针或逆时针。

 plt.figtext(0.52, 0.95, '设置极坐标(ρ, 0)的位置', ha='center', size=20,fontproperties=zhfont)#设置figure的标题
 plt.savefig('0_degrees.jpg')
 plt.show()

set_theta_zero_location(loc, offset=0.0)
　　Sets the location of theta’s zero. (Calls set_theta_offset with the correct value in radians under the hood.)

loc : str
　　May be one of “N”, “NW”, “W”, “SW”, “S”, “SE”, “E”, or “NE”.
offset : float, optional
　　An offset in degrees to apply from the specified loc. Note: this offset is always applied counter-clockwise regardless of the direction setting.

reference: https://matplotlib.org/api/projections_api.html?highlight=set_theta_zero_location#matplotlib.projections.polar.PolarAxes.set_theta_zero_location