为什么在Matplotlib中3D绘图必须Z是二维的 [英] Why Z has to be 2-dimensional for 3d plotting in matplotlib

问题描述

我正在尝试使用表面图.html"rel =" nofollow noreferrer>此网站使用matplotlib:

I am trying to plot 3d Surface plots using code from this site using matplotlib:

X，Y和Z的计算如下:

X,Y and Z are obtained as below:

from math import pi
from numpy import cos, meshgrid
alpha = 0.7
phi_ext = 2 * pi * 0.5

def flux_qubit_potential(phi_m, phi_p):
    return 2 + alpha - 2 * cos(phi_p)*cos(phi_m) - alpha * cos(phi_ext - 2*phi_p)

phi_m = linspace(0, 2*pi, 100)
phi_p = linspace(0, 2*pi, 100)
X,Y = meshgrid(phi_p, phi_m)
Z = flux_qubit_potential(X, Y).T

然后使用以下代码完成3d绘制:

And 3d plotting is done with following code:

from mpl_toolkits.mplot3d.axes3d import Axes3D

fig = plt.figure(figsize=(14,6))

# `ax` is a 3D-aware axis instance, because of the projection='3d' keyword argument to add_subplot
ax = fig.add_subplot(1, 2, 1, projection='3d')

p = ax.plot_surface(X, Y, Z, rstride=4, cstride=4, linewidth=0)

# surface_plot with color grading and color bar
ax = fig.add_subplot(1, 2, 2, projection='3d')
p = ax.plot_surface(X, Y, Z, rstride=1, cstride=1, cmap=cm.coolwarm, linewidth=0, antialiased=False)
cb = fig.colorbar(p, shrink=0.5)

但是，如果我用x，y，z 3d数据替换X，Y和Z(下面的示例给出)，则存在一个错误，即 Z必须是二维的.如何使用通常的x，y，z值进行绘制，如下所示:

However, if I replace X,Y and Z by my x,y,z 3d data (sample give below), there is an error that Z has to be 2 dimensional. How can I plot with usual x,y,z values, as following:

   x   y   z
0  12  0  0.1
1  13  1  0.8
2  14  3  1.0
3  16  4  1.2
4  18  4  0.7

推荐答案

根据我的理解，这是因为要绘制表面，您需要形成散点图或

This is because, in my understanding, to draw a surface you need to form a polygon mesh. To draw a 3d surface, you need to have small squares, for example, on the xy-plane and then have 1 corresponding z value for all the x-y points. The smaller the area of the square means finer mesh-grid and better resolution(smooth-looking surface.) Now if you have an arbitrary set of xyz points, how matplotlib can determine which surface to draw. That is why a mesh is required. You can of course plot 3d scatter or line plots with your data.

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