用颜色绘制单位球面上的数据

Question

嗨我有三列数据集：theta，phi和atta和phi的函数值。我想将这些数据投影到单位球体上，使得球体上的颜色与函数的大小相对应，与this post的意义相似。我提供样本的数据的性质是球体的上半部分和下半部分的值是相同的，因此期望球体的上半部分和下半部分的颜色分布是相同的，但出于某种原因，我发现尽管形状是正确的，但由于某些原因，上半部分更亮（见下图）。有谁知道为什么会这样？

数据集：

Theta     Phi      Values
0.000000 -3.141592 0.500000
0.000000 -3.078126 0.500000
0.000000 -3.014659 0.500000
...    ...  ...
0.031733 -3.141592 0.499497
0.031733 -3.078126 0.499497
0.031733 -3.014659 0.499497
...    ...  ...
0.507732 -0.031733 0.388763
0.507732  0.031734 0.388763
0.507732  0.095200 0.388541
...    ...  ...
1.364530 -0.095199 0.131597
1.364530 -0.031733 0.135245
1.364530 0.031734 0.135245
1.364530 0.095200 0.131597
...    ...  ...
2.633860 -0.095199 0.388541
2.633860 -0.031733 0.388763
2.633860  0.031734 0.388763
...    ...  ...    
3.109859 3.014660 0.499497
3.109859 3.078126 0.499497
3.109859 3.141593 0.499497
...    ...  ...
3.141592 3.014660 0.500000
3.141592 3.078126 0.500000
3.141592 3.141593 0.500000

代码：

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

#theta inclination angle
#phi azimuthal angle
n_theta = 100 #number of values for theta
n_phi = 100  #number of values for phi
r = 1        #radius of sphere

theta, phi = np.mgrid[0: pi:n_theta*1j,-pi:pi:n_phi*1j ]

x = r*np.sin(theta)*np.cos(phi)
y = r*np.sin(theta)*np.sin(phi)
z = r*np.cos(theta)

print theta.shape 
print phi.shape 

inp = []
f = open("datafile.dat","r")
for line in f:
    i = float(line.split()[0])
    j = float(line.split()[1])
    val = float(line.split()[2])
    inp.append([i, j, val])

inp = np.array(inp)
#print inp
#print inp.shape

#reshape the input array to the shape of the x,y,z arrays. 
c = inp[:,2].reshape((n_phi,n_theta))

#Set colours and render
fig = plt.figure(figsize=(10, 8))
ax = fig.add_subplot(111, projection='3d')

surf = ax.plot_surface(
    x,y,z,  rstride=1, cstride=1, facecolors=cm.hot(c), alpha=0.9, linewidth=1) 
ax.set_xlim([-2.0,2.0])
ax.set_ylim([-2.0,2.0])
ax.set_zlim([-2,2])
ax.set_aspect("equal")

plt.title('Projecting data on unit sphere')

#Label axis. 
ax.set_xlabel('X')
ax.set_ylabel('Y')
ax.set_zlabel('Z')

#Creates array for colorbar from 0 to 1. 
a = array( [1.0, 0.5, 0.0])

#Creates colorbar
m = cm.ScalarMappable(cmap=cm.hot)
m.set_array(a)
plt.colorbar(m)
plt.savefig('Projecting data on unit sphere.png')

f.close()
plt.show()

Answer 1

您需要将plot_surface的{​​{1}}参数设置为shade，

False

否则会在表面上模拟一些光效，这取决于视角。