多边形或线内的质心

Question

在 geopandas 中，我使用此代码从几何参数创建质心参数。

df["center"]=df.centroid

我想强制计算质心在多边形内。 在这里我在 R 中找到了一些东西。我可以在 python 中做吗？

Calculate Centroid WITHIN / INSIDE a SpatialPolygon

Answer 1

要获得始终落在其相应多边形内的代表点，可以在geopandas 中使用名为representative_point() 的函数来完成。这是一个创建和绘制多边形及其代表的演示代码。点。

import pandas as pd
import geopandas as gpd
from shapely import wkt
from shapely.geometry import Point, Polygon
from shapely.wkt import loads

#Create some test data
d = {'col1': [1,2],
     'wkt': [
         'POLYGON ((700000 5500000, 700000 5600000, 800000 5600000, 800000 5500000, 700000 5500000))',
        """POLYGON ((1441727.5096940901130438 6550163.0046194596216083, 
                     1150685.2609429201111197 6669225.7427449300885201, 
                     975398.4520359700545669 6603079.7771196700632572, 
                     866257.6087542800232768 6401334.5819626096636057, 
                     836491.9242229099618271 6106985.0349301798269153, 
                     972091.1537546999752522 5835786.5758665995672345, 
                     1547561.0546945100650191 5782869.8033663900569081, 
                     1408654.5268814601004124 5600968.3978968998417258, 
                     720736.4843787000281736 5663807.0652409195899963, 
                     598366.4479719599476084 6001151.4899297598749399, 
                     654590.5187534400029108 6341803.2128998702391982, 
                     869564.9070355399744585 6784981.1825891500338912, 
                     1451649.4045378800947219 6788288.4808704098686576, 
                     1441727.5096940901130438 6550163.0046194596216083))"""

     ]
    }
df = pd.DataFrame( data=d )
gdf = gpd.GeoDataFrame(df, \
                   crs={'init': 'epsg:3857'}, \
                   geometry=[loads(pgon) for pgon in df.wkt])
gdf4326 = gdf.to_crs(4326)  #coordinates in plain degrees

# create 2nd geometry column, for representative points
gdf4326["geometry2"] = gdf4326.representative_point()

# plot all layers of geometries
ax1 = gdf4326.plot(color="gray", alpha=0.5)  # the polygons
gdf4326.set_geometry('geometry2').plot(zorder=10, color='red', ax=ax1) # the rep_points