如果Line与多边形相交,则返回一个布尔值

时间:2020-09-08 01:11:46

标签: python matplotlib shapely

当它们与多边形相交时,如何使行列表返回布尔值列表,结果是不显示返回True值的线?

当前,我的代码在原点(0,0)到XY笛卡尔平面上的所有点之间绘制了一条线。我希望能够使与多边形相交的线返回布尔值。希望这将使我不显示返回True值的行。

即 IF Lineintersection ==真: 不显示行 其他: 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

1 个答案:

答案 0 :(得分:0)

我想您可以通过从两个for循环中删除多边形创建来简化代码,例如,通过在创建线条之前创建多边形(另请注意,您在原始代码中创建了两次)代码,一次在clip_poly变量中,一次在polygon变量中。)

然后,您将能够调用要处理的几何对象的intersects方法(此处为polygonline)。

我在一个循环中简化了两个for循环,直接解压缩了x1y1坐标(并且我还将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()

ResultPlot