如何在 python 中绘制多边形（给出坐标）并为其边缘编号？

Question

我有一个 python 中的农林业地块（多边形）列表。每个多边形都表示为纬度/经度。

 polygon1_coords = [
    (11.946898956, -86.109286248),
    (11.947196373, -86.109159886),
    (11.947092456, -86.108962101),
    (11.946897164, -86.10886504),
    (11.946898956, -86.109286248 )]

polygon2_coords = [
    (11.946895372, -86.110055411),
    (11.94718204,  -86.110046254),
    (11.947194581, -86.109172705),
    (11.946900747, -86.109313718),
    (11.946895372, -86.110055411)
    ]

我需要一种方法将这些多边形绘制为图像并在其边缘放置数字。多边形也需要用字母表示。这是我需要的例子

如您所见，我需要能够在同一张图片中表示多个多边形，并分别对其边进行编号。我怎样才能在 python 中做到这一点？

Answer 1

Python 中有几个库允许您绘制多边形形状并对其进行注释。下面是一个使用 Matplotlib 库的示例：

import matplotlib.pyplot as plt

polygon = [
    (12.132481, -86.239511),
    (12.132093,-86.239344 ),
    (12.132287, -86.23876),
    (12.132481, -86.239511)
]

x = [p[0] for p in polygon]
y = [p[1] for p in polygon]

fig, ax = plt.subplots()
ax.plot(x, y)

for i, p in enumerate(polygon):
    ax.annotate(f"{i+1}", (p[0], p[1]))

plt.show()

此代码将多边形显示为一系列连接的线段，并用边号注释每个顶点。要用字母表示多边形，只需在 ax.annotate 函数中将 f"{i+1}" 替换为所需的字母即可。

Answer 2

借用之前的答案，但不仅在边缘添加标签，还在多边形内部添加标签，您可以使用shapely's representative_point 为您的标签找到一个位置，请参阅：

import matplotlib.pyplot as plt
from shapely.geometry import Polygon

polygon = [
    (12.132481, -86.239511),
    (12.132093,-86.239344 ),
    (12.132287, -86.23876),
    (12.132481, -86.239511)
]

x = [p[0] for p in polygon]
y = [p[1] for p in polygon]

label_location = Polygon(polygon).representative_point()

fig, ax = plt.subplots()
ax.plot(x, y)

#[:-1] slice because we only want to print 3 edges, not where they meet
for i, p in enumerate(polygon[:-1]):
    ax.annotate(f"{i+1}", (p[0], p[1]))

ax.annotate("B", label_location.coords[:][0])

plt.show()

情节：