如何在使用interpolate.interp2d绘制曲面后从给定的Z值中获取X，Y值

Question

我有x和y数组来表示网格数据的行和列，它的值在z 2d数组中。我使用interpolate.interp2d绘制表面图。现在，我能够获得给定x，y值的z值，但我希望能够从给定的z值获得x，y值。

码：

import numpy as np
import matplotlib.pyplot as plt
from matplotlib import cm
from mpl_toolkits.mplot3d import Axes3D
from scipy import interpolate

x = [0, 0.01, 0.02]
y = [0, 5e-05, 0.0001]
print(np.meshgrid(x, y))
xx, yy = np.meshgrid(x, y)
z = [[ 1.    ,      0.99990035,  0.99981654],
 [ 0.90849264,  0.85447203,  0.81382534],
 [ 0.82880434 , 0.76083003 , 0.71961281]]
f = interpolate.interp2d(x, y, z, kind='linear')
xnew = np.arange(x[0],x[2], 1e-6)
ynew = np.arange(y[0],y[2], 1e-6)

znew = f(xnew, ynew)
print(f(0.003,0.0006))
xnew,ynew=np.meshgrid(xnew,ynew)

fig = plt.figure()
ax = fig.gca(projection='3d')

ax.plot_surface(xnew,ynew, znew,
                       cmap=cm.get_cmap('coolwarm'))

plt.show()

Answer 1

无论如何绘制曲面，您可以沿特定的z值添加等高线图。为了从给定的z值获得x，y值，ob可以使用轮廓线的数据。

c = ax.contour(xnew,ynew,znew, [f(0.003,0.0006)])
line = c.allsegs[0][0]
print(line)

得到的line是一个二维数组，第一列中的x值和第二列中的y值。

import numpy as np
import matplotlib.pyplot as plt
from matplotlib import cm
from mpl_toolkits.mplot3d import Axes3D
from scipy import interpolate

x = [0, 0.01, 0.02]
y = [0, 5e-05, 0.0001]
xx, yy = np.meshgrid(x, y)
z = [[ 1.    ,      0.99990035,  0.99981654],
    [ 0.90849264,  0.85447203,  0.81382534],
    [ 0.82880434 , 0.76083003 , 0.71961281]]

f = interpolate.interp2d(x, y, z, kind='linear')

xnew = np.arange(x[0],x[2], 1e-6)
ynew = np.arange(y[0],y[2], 1e-6)
znew = f(xnew, ynew)
print(f(0.003,0.0006))
xnew,ynew=np.meshgrid(xnew,ynew)

fig = plt.figure()
ax = fig.gca(projection='3d')

ax.plot_surface(xnew,ynew, znew,
                       cmap=cm.get_cmap('coolwarm'))

c = ax.contour(xnew,ynew,znew, [f(0.003,0.0006)])
line = c.allsegs[0][0]
print(line)
ax.view_init(elev=13, azim=18)
plt.show()