在matplotlib contour-plot中手动设置标签错误

Question

我正在尝试在下面的代码中将手动标签添加到等值线图中。标签随机打印。有谁知道如何解决这个问题？这似乎是Matplotlib中的一个错误。

此致 大卫

import numpy as np
import matplotlib.pyplot as plt

a = 0.2

resolution = 100
xarray = np.linspace(0,0.25,num=resolution)
yarray = np.linspace(0,1,num=resolution)

A = np.empty([resolution,resolution])

xc = 0
yc = 0
for x in xarray:
    for y in yarray:
        #print xc,yc

        wp = 1./np.pi*np.arctan(np.sin(np.pi*y)*np.sinh(np.pi*a/2.)/
              (np.cosh(np.pi*x)-np.cos(np.pi*y)*np.cosh(np.pi*a/2.)))

        if wp <= 0:
            wp = wp+1
            A[xc, yc] = wp
        else:
            A[xc, yc] = wp
        yc += 1
    yc=0
    xc += 1

A = A.transpose()
B = np.fliplr(A)
AB = np.hstack((B,A))
fullx = np.hstack((-xarray[::-1],xarray))

#plot
fig = plt.figure()
fig.suptitle("Weighting potential")
ax = plt.subplot(1,1,1)
CS = plt.contour(fullx,yarray,AB,10, colors='k')

labelpos = np.dstack((np.zeros(9),np.arange(0.1,1,0.1)))[0]
plt.clabel(CS,inline=True, fmt='%1.1f',fontsize=9, manual=labelpos)

plt.show()

Answer 1

这是预期的行为。

它为x, y参数中包含的每个manual数据坐标选择最接近的轮廓曲线。当找到许多坐标的相同轮廓曲线时，可能会发生它们会开始凝聚，就像你的情况一样。

如果您使用：

y_pick = [0.01, 0.025, 0.05, 0.075, 0.1, 0.15, 0.2, 0.3, 0.5]
labelpos = ((0, i) for i in y_pick)

你会得到类似的东西：

---

超出主题：

您可以对代码进行矢量化，避免相对较慢的for循环：

import numpy as np
import matplotlib.pyplot as plt

a = 0.2

def fwp(x, y, a):
    return (1./np.pi*np.arctan(np.sin(np.pi*y)*np.sinh(np.pi*a/2.)/
          (np.cosh(np.pi*x)-np.cos(np.pi*y)*np.cosh(np.pi*a/2.))))

resolution = 100
xarray = np.linspace(0, 0.25, num=resolution)
yarray = np.linspace(0, 1, num=resolution)
x, y = np.meshgrid(xarray, yarray, copy=False)
A = fwp(x, y, a)
A[A<=0] += 1
B = np.fliplr(A)
AB = np.hstack((B, A))