将NumPy 2D阵列中的所有2D点连接为三角形网格 [英] Connect all 2D Points from NumPy 2D Arrays as a triangular meshgrid

问题描述

我对Python来说还很陌生，我正试图绘制一个像这样的三角形网格:

I am pretty new to Python and I am trying to plot a triangular grid like this:

import matplotlib.pyplot as plt
import numpy as np

r   = 0.25
d   = 2*r
s   = 0

l1 = np.array([[s,0], [s+d,0], [s+2*d,0], [s+3*d,0]]) 
l2 = np.array([[s-r,d], [s+r,d], [s+r+d,d], [s+r+2*d,d]])
l3 = np.array([[s,2*d], [s+d,2*d], [s+2*d,2*d], [s+3*d,2*d]])
l4 = np.array([[s-r,3*d], [s+r,3*d], [s+r+d,3*d], [s+r+2*d,3*d]])
l5 = np.array([[s,4*d], [s+d,4*d], [s+2*d,4*d], [s+3*d,4*d]])

plt.scatter(*zip(*l1))
plt.scatter(*zip(*l2))
plt.scatter(*zip(*l3))
plt.scatter(*zip(*l4))
plt.scatter(*zip(*l5))

plt.show

我的问题是，我不知道如何连接所有点.我为所有l添加了带有plt.plot(*zip(*l1))的水平线，但是我不知道如何绘制垂直"之字形线...有人有简单"的解决方案吗?

My problem is, that I have no real clue how to connect all points. I have added horizontal lines with plt.plot(*zip(*l1)) for all l but I have no idea how to draw the 'vertical' zigzag lines... Has anybody a 'simple' solution?

非常感谢！

推荐答案

triplot is made for that purpose: plotting triangles. You can either pass only x and y coordinates (in this case a Delaunay triangulation will be computed), or a full Triangulation object to which you can specify your own triangles.

import matplotlib.pyplot as plt
import numpy as np
import matplotlib.tri as mtri

r = 0.25
d = 2*r
s = 0

def meshgrid_triangles(n, m):
    """ Returns triangles to mesh a np.meshgrid of n x m points """
    tri = []
    for i in range(n-1):
        for j in range(m-1):
            a = i + j*(n)
            b = (i+1) + j*n
            d = i + (j+1)*n
            c = (i+1) + (j+1)*n
            if j%2 == 1:
                tri += [[a, b, d], [b, c, d]]
            else:
                tri += [[a, b, c], [a, c, d]]
    return np.array(tri, dtype=np.int32)


x0 = np.arange(4) * d
y0 = np.arange(5) * d
x, y = np.meshgrid(x0, y0)
x[1::2] -= r
triangles = meshgrid_triangles(4, 5)
triangulation = mtri.Triangulation(x.ravel(), y.ravel(), triangles)
plt.scatter(x, y, color='red')
plt.triplot(triangulation, 'g-h')

plt.show()

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