多个y轴使用matplotlib无法正常工作

Question

我使用下面的代码使用带有4个参数X=depth, y1=temp, y2=salinity, y3=velocity的matplotlib绘制图形但是速度值没有正确显示，并且当具有恒定比例值的缩放时，第2和第3轴不可调整（比例值）为1 ，我怎么能让它可调（比例值），我的意思是当放大缩小时，所有轴的比例值都是可变的。

 from mpl_toolkits.axes_grid1 import host_subplot
 import mpl_toolkits.axisartist as AA
 import matplotlib.pyplot as plt
 import numpy as np

 if 1:

    host = host_subplot(111, axes_class=AA.Axes)
    plt.subplots_adjust(right=0.75)

    par1 = host.twinx()
    par2 = host.twinx()

    offset = 60
    new_fixed_axis = par2.get_grid_helper().new_fixed_axis
    par2.axis["right"] = new_fixed_axis(loc="right", axes=par2, offset=  
    (offset, 0))

    par2.axis["right"].toggle(all=True)

   # host.set_xlim(0, 2)
    #host.set_ylim(0, 2)

    host.set_xlabel("Depth")
    host.set_ylabel("Temperature")
    par1.set_ylabel("Salinity")
    par2.set_ylabel("Velocity")
    x  = np.array([0,5,10,15,20,25,30,35])
    y1 = np.array([30.340,30.080,29.116,28.395,28.093,28.040,27.975,27.872])
    y2 = np.array([33.130,34.046,35.119,34.933,34.764,34.824,34.860,34.852])
    y3 = np.array([1544.296, 1544.787, 1543.452,1542.280,1541.522,1544.548,1541.523,1541.368])

    p1, = host.plot(x, y1, label="Temperature")
    p2, = par1.plot(x, y2, label="Salinity")
    p3, = par2.plot(x, y3, label="Velocity")

    #par1.set_ylim(0, 4)
    #par2.set_ylim(1, 65)

    host.legend()

    host.axis["left"].label.set_color(p1.get_color())
    par1.axis["right"].label.set_color(p2.get_color())
    par2.axis["right"].label.set_color(p3.get_color())

    plt.draw()
    plt.show()

Answer 1

以下示例以您建议的方式运行：http://matplotlib.org/examples/pylab_examples/multiple_yaxis_with_spines.html

基本上，他们避免使用“new_fixed_axis”函数：

from mpl_toolkits.axes_grid1 import host_subplot
import mpl_toolkits.axisartist as AA
import matplotlib.pyplot as plt
import numpy as np

fig,host = plt.subplots()
fig.subplots_adjust(right=0.75)

par1 = host.twinx() 
par2 = host.twinx()

par2.spines["right"].set_position(("axes", 1.2))
par2.spines["right"].set_visible(True)

host.set_xlabel("Depth")
host.set_ylabel("Temperature")
par1.set_ylabel("Salinity")
par2.set_ylabel("Velocity")

x  = np.array([0,5,10,15,20,25,30,35])
y1 = np.array([30.340,30.080,29.116,28.395,28.093,28.040,27.975,27.872])
y2 = np.array([33.130,34.046,35.119,34.933,34.764,34.824,34.860,34.852])
y3 = np.array([1544.296, 1544.787, 1543.452,1542.280,1541.522,1544.548,1541.523,1541.368])

p1, = host.plot(x, y1, 'b', label="Temperature")
p2, = par1.plot(x, y2, 'r', label="Salinity")
p3, = par2.plot(x, y3/10, 'g', label="Velocity/00")

host.yaxis.label.set_color(p1.get_color())
par1.yaxis.label.set_color(p2.get_color())
par2.yaxis.label.set_color(p3.get_color())

tkw = dict(size=4, width=1.5)
host.tick_params(axis='y', colors=p1.get_color(), **tkw)
par1.tick_params(axis='y', colors=p2.get_color(), **tkw)
par2.tick_params(axis='y', colors=p3.get_color(), **tkw)
host.tick_params(axis='x', **tkw)

host.legend()
plt.show()

奇怪的y轴刻度仍有一点问题，但至少它们可以放大+平移：）。