Spherical Grid

Plot a grid in spherical coordinates with rho = 1 as Cartesian points. We can see that the Cartesian distances between points are not regular and there are many points that were converted to the same Cartesian point at the poles of the sphere.

import matplotlib.pyplot as plt
import numpy as np

import pytransform3d.coordinates as pc
from pytransform3d.plot_utils import make_3d_axis

thetas, phis = np.meshgrid(
    np.linspace(0, np.pi, 11), np.linspace(-np.pi, np.pi, 21)
)
rhos = np.ones_like(thetas)
spherical_grid = np.column_stack(
    (rhos.reshape(-1), thetas.reshape(-1), phis.reshape(-1))
)
cartesian_grid = pc.cartesian_from_spherical(spherical_grid)

ax = make_3d_axis(ax_s=1, unit="m", n_ticks=6)
ax.scatter(cartesian_grid[:, 0], cartesian_grid[:, 1], cartesian_grid[:, 2])
ax.plot(cartesian_grid[:, 0], cartesian_grid[:, 1], cartesian_grid[:, 2])
plt.show()