how to scale a polar plotted sphere up to a different radius? python

So i need to scale up the size of a sphere i plotted with polar coordinates, but I am unsure if Im doing it correctly in a way that scales properly.

#og code
import matplotlib.pyplot as plt
import numpy as np
plt.rcParams["figure.figsize"] = [7.00, 3.50]
plt.rcParams["figure.autolayout"] = True
fig = plt.figure()
ax = fig.add_subplot(projection='3d')
r = 0.05
u, v = np.mgrid[0:2 * np.pi:30j, 0:np.pi:20j]
x = np.cos(u) * np.sin(v)
y = np.sin(u) * np.sin(v)
z = np.cos(v)
ax.plot_surface(x, y, z, cmap=plt.cm.YlGnBu_r)
plt.show()
#no matter what I change r to its always .5 by .5 units on a plot. I want it to be a radius of 50. 

first sphere
I then tried this and it returns a sphere the size I want, but I am unsure if the z coordinate is scaling the same rate as the rest because it doesn't look as spherical.

import matplotlib.pyplot as plt
import numpy as np
plt.rcParams["figure.figsize"] = [10.00, 40.50]
plt.rcParams["figure.autolayout"] = False
fig = plt.figure()
ax = fig.add_subplot(projection='3d')
ax.axes.set_xlim3d(left=-100, right=100) 
ax.axes.set_ylim3d(bottom=-100, top=100) 
ax.axes.set_zlim3d(bottom=-100, top=100) 
    
r = 50
u, v = np.mgrid[0:2 * np.pi:300j, 0:np.pi:300j]
x = 100*(np.cos(u) * np.sin(v))
y = 100*(np.sin(u) * np.sin(v))
z = 100*(np.cos(v))
ax.plot_surface(x, y, z, rstride= 5, cstride = 5, cmap=plt.cm.YlGnBu_r)
plt.show()```
[second sphere](https://i.stack.imgur.com/qOGaX.png)


I tried to just add more points to plot and scaling them by multiplying by 100. not sure if spherical or tripping. 

</details>


# 答案1
**得分**: 2

使用 `ax.set_box_aspect()` 来确保所有的坐标轴按相同的比例缩放（沿着X、Y和Z轴的纵横比）。[查看相关文档](https://matplotlib.org/stable/api/_as-gen/matplotlib.axes.Axes.set_box_aspect.html)

您可以通过传递硬编码的值或通过使用 `np.ptp()` 函数动态获取 `x`、`y` 和 `z` 值的总范围来实现这一点。

```python
# 硬编码的值可以是 (200, 200, 200)
ax.set_box_aspect((np.ptp(x), np.ptp(y), np.ptp(z))

ax.plot_surface(x, y, z, rstride= 5, cstride = 5, cmap=plt.cm.YlGnBu_r)
plt.show()

这应该为您提供以下图形

关于半径，您没有使用您定义的 r 变量。使用 r 缩放 x、y 和 z 应该有效:

# 保持与前面图形相同的盒子纵横比，以演示缩放效果
ax.set_box_aspect((200, 200, 200))

x = r*(np.cos(u) * np.sin(v))
y = r*(np.sin(u) * np.sin(v))
z = r*(np.cos(v))

在这里，r=50 将生成以下图形:

[...]

# Hard coded values would be (200, 200, 200)
ax.set_box_aspect((np.ptp(x), np.ptp(y), np.ptp(z))

ax.plot_surface(x, y, z, rstride= 5, cstride = 5, cmap=plt.cm.YlGnBu_r)
plt.show()

# Keep same box aspect as previous figure to demonstrate the scaling effect
ax.set_box_aspect((200, 200, 200))  

x = r*(np.cos(u) * np.sin(v))
y = r*(np.sin(u) * np.sin(v))
z = r*(np.cos(v))