Question

我有一个3D numpy数组，其尺寸为1400x1400x29。但是，数据是4D的，因为每个x，y，z都有一个不同的值（第4维）。我相信可以做到以下类似的事情。

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

//some calculation that creates a 3D array  called "cube"

fig = plt.figure()
ax = fig.add_subplot(111, projection='3d')
for x in range(1400):
    for y in range(1400):
        for z in range(29):
            ax.scatter(x, y, z, c=cube[x,y,z])
plt.show()

但是，以上脚本给我一个错误提示 “ TypeError：类型为'numpy.float64'的对象没有len（）”

编辑1 完整的错误消息

File "cube.py", line 57, in <module>
    ax.scatter(x, y, z, c=cube[z , x , y], cmap=plt.hot())
  File "/pawsey/cle60up05/python/2.7.14/matplotlib/2.1.0/lib/python2.7/site-packages/matplotlib-2.1.0-py2.7-linux-x86_64.egg/mpl_toolkits/mplot3d/axes3d.py", line 2353, in scatter
    xs, ys, s=s, c=c, *args, **kwargs)
  File "/pawsey/cle60up05/python/2.7.14/matplotlib/2.1.0/lib/python2.7/site-packages/matplotlib-2.1.0-py2.7-linux-x86_64.egg/matplotlib/__init__.py", line 1710, in inner
    return func(ax, *args, **kwargs)
  File "/pawsey/cle60up05/python/2.7.14/matplotlib/2.1.0/lib/python2.7/site-packages/matplotlib-2.1.0-py2.7-linux-x86_64.egg/matplotlib/axes/_axes.py", line 4050, in scatter
    colors = mcolors.to_rgba_array(c)
  File "/pawsey/cle60up05/python/2.7.14/matplotlib/2.1.0/lib/python2.7/site-packages/matplotlib-2.1.0-py2.7-linux-x86_64.egg/matplotlib/colors.py", line 231, in to_rgba_array
    result = np.empty((len(c), 4), float)
TypeError: object of type 'numpy.float64' has no len()

谢谢

Answer 1

因此，了解cube是形状为numpy.ndarray的{{1}}时，绘制3D散点的正确方法是：

(1400, 1400, 29)

您必须使用数组而不是标量调用import matplotlib.pyplot as plt import numpy as np from mpl_toolkits.mplot3d import Axes3D //some calculation that creates a 3D array called "cube" fig = plt.figure() ax = fig.add_subplot(111, projection='3d') X, Y, Z = np.mgrid[:1400, :1400, :29] ax.scatter(X, Y, Z, c=cube.ravel()) plt.show()。另外，它需要一个1D数组作为ax.scatter的输入，所以我叫c。 ravel()只是创建N维均匀网格的一种快速方法。它等效于np.mgrid中的np.meshgrid。如果您想了解更多信息，建议您阅读每个文档。

使用matplotlib绘制4D numpy数据

1 个答案: