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我想在给定的点上绘制曲面。我想获得任意点的z坐标。我不明白为什么scipy.interpolate.griddata和scipy.interpolate.RectBivariateSpline为相同的x和y坐标返回不同的值。我哪里做错了?为什么scipy.interpolate.griddata和scipy.interpolate.RectBivariateSpline返回不同的值?
import numpy as np
from scipy.interpolate import griddata, RectBivariateSpline
from mpl_toolkits.mplot3d import Axes3D
import matplotlib.pyplot as plt
x_list = np.array([ 10.0, 10.0, 0.0, 0.0])
y_list = np.array([ 0.0, 10.0, 10.0, 0.0])
z_list = np.array([103.95, 105.5, 104.85, 104.6])
xi = np.linspace(min(x_list), max(x_list),11)
yi = np.linspace(min(y_list), max(y_list),11)
grid_x, grid_y = np.meshgrid(xi, yi)
grid_z1 = griddata((x_list, y_list), z_list, (grid_x, grid_y), method='nearest')
grid_z2 = griddata((x_list, y_list), z_list, (grid_x, grid_y), method='linear')
grid_z3 = griddata((x_list, y_list), z_list, (grid_x, grid_y), method='cubic')
z = RectBivariateSpline(xi, yi, grid_z2, kx=1, ky=1, s=0)
print z(10.0, 0.0)[0,0] #return 104.85!!! Must be 103.95.
fig = plt.figure()
ax1 = fig.add_subplot(221, projection='3d')
surf = ax1.plot_surface(grid_x, grid_y, grid_z1)
ax1.set_xlabel(u'X')
ax1.set_ylabel(u'Y')
ax1.set_zlabel(u'Z')
ax2 = fig.add_subplot(222, projection='3d')
surf = ax2.plot_surface(grid_x, grid_y, grid_z2)
ax2.set_xlabel(u'X')
ax2.set_ylabel(u'Y')
ax2.set_zlabel(u'Z')
ax3 = fig.add_subplot(223, projection='3d')
surf = ax3.plot_surface(grid_x, grid_y, grid_z3)
ax3.set_xlabel(u'X')
ax3.set_ylabel(u'Y')
ax3.set_zlabel(u'Z')
plt.show()
它们不就是不同的插值方法吗?你不能指望这些值完全相同。 – BrenBarn 2014-11-14 22:34:16
我不确定你想要用你的代码做什么,但是你可能会陷入'np.meshgrid'的Matlabesque行为。看到这个讨论[这里](https://github.com/scipy/scipy/issues/3164)。 TLDR:改变meshgrid的输入顺序,然后再试一次 – cd98 2014-11-14 22:59:15
是的,只需要改变:'grid_y,grid_x = np.meshgrid(xi,yi)',我认为现在应该起作用。 (如果您确认这是问题,请解释回答中发生了什么,以便回到此问题的人确切知道发生了什么) – cd98 2014-11-14 23:02:49