Return 如果直线与多边形相交，则为布尔值

Question

如何让我的行列表 return 成为布尔值列表，当它们与多边形相交时，不显示 return 为真值的行？

目前我的代码绘制了一条从原点 (0,0) 到 XY 笛卡尔平面上所有点的线。我希望能够使与多边形 return 相交的线成为布尔值。这有望让我不显示 return 为真值的行。

即 IF Lineintersection == True：不显示线别的：显示行

origin = [0,0]
import numpy as np
import matplotlib.pyplot as plt
from shapely.geometry import LineString
from shapely.geometry import Point, Polygon
import descartes

quality = 7
x = np.linspace(-1,1,quality)
y = np.linspace(-1,1,quality)
X,Y = np.meshgrid(x,y)
polycoords = [[-1, 1], [-1, 0.5], [0, 0.5], [0, 1]]
clip_poly = shapely.geometry.Polygon(polycoords)

positions = np.vstack([Y.ravel(), X.ravel()])

#plt.scatter(*positions[::-1])

fig = plt.figure()
ax = fig.add_subplot(111)

for i in range(len(positions)):
    for j in range(len(positions[i])):
        plt.scatter(*positions[::-1])
        x1 = positions[0][j]
        y1 = positions[1][j]
        line = LineString([origin, (x1, y1)])
        x2, y2 = line.xy
        lines = plt.plot(0, 0, x2, y2, color='green', linewidth=1, solid_capstyle='round')
        polygon = Polygon(polycoords)
        polygonbuilding = ax.add_patch(descartes.PolygonPatch(clip_poly, fc='pink', alpha=0.3))
plt.show()

Result from above code

Answer 1

我想您可以通过从两个 for 循环中删除多边形创建来简化您的代码，例如通过在创建线之前创建多边形（另外请注意，您在您的原始代码，一次在 clip_poly 变量中，一次在 polygon 变量中）。

然后您将能够调用您正在处理的几何对象的 intersects 方法（此处为 polygon 和 line）。

我将你的两个 for 循环简化为一个循环，直接解包 x1 和 y1 坐标（我还将 plt.scatter 调用移到了循环之外):

import numpy as np
import matplotlib.pyplot as plt
from shapely.geometry import LineString
from shapely.geometry import Point, Polygon
import descartes

origin = [0,0]
quality = 7
x = np.linspace(-1,1,quality)
y = np.linspace(-1,1,quality)
X,Y = np.meshgrid(x,y)
polycoords = [[-1, 1], [-1, 0.5], [0, 0.5], [0, 1]]
positions = np.vstack([Y.ravel(), X.ravel()])

fig = plt.figure()
ax = fig.add_subplot(111)

polygon = Polygon(polycoords)
polygonbuilding = ax.add_patch(
    descartes.PolygonPatch(polygon, fc='pink', alpha=0.3))
plt.scatter(*positions[::-1])
    
for x1, y1 in positions.T:
    line = LineString([origin, (x1, y1)])
    if not polygon.intersects(line):  # <- the condition you were looking for
        x2, y2 = line.xy
        plt.plot(0, 0, x2, y2, color='green', linewidth=1, solid_capstyle='round')

plt.show()

Return 如果直线与多边形相交，则为布尔值

Return a Boolean if Line intersects a Polygon

python

matplotlib

shapely