使用Python编程语言中的Geopandas库来读取多边形形状文件。首先,需要使用Shapely库计算每个多边形的中心点,然后使用OSMnx库下载所需区域的街道网络。接下来,使用OSMnx库中的方向计算功能来计算每个路段的方向,并将路段方向分配给跨越多个多边形的任何路段。然后,将每个多边形中的路段方向分组,以计算该多边形的平均方向和方向分散度。最后,将熵计算公式应用于每个多边形的路段方向分布,以计算该多边形的网络熵值。示例代码如下:
import geopandas as gpd
from shapely.geometry import Point
import osmnx as ox
import numpy as np
Read in shapefile and calculate centroid
polygons = gpd.read_file('shapefile.shp')
polygons['centroid'] = polygons.centroid
Download street network using OSMnx
G = ox.graph_from_place('City, State, Country', network_type='all')
Calculate street network orientation
orientations = ox.get_edge_bearings(G)
Assign edge orientations to polygons
for i in range(len(polygons)):
polygon = polygons.iloc[i]
edges = ox.get_polygon_nodes(G, polygon.geometry.exterior.coords)
orientations_subset = orientations.loc[edges]
orientations_subset = orientations_subset[~orientations_subset.isna()]
if len(orientations_subset) > 0:
orientations_mean = np.mean(orientations_subset)
orientations_std = np.std(orientations_subset)
polygon['orientation'] = orientations_mean
polygon['orientation_std'] = orientations_std
else:
polygon['orientation'] = np.nan
polygon['orientation_std'] = np.nan
Calculate network entropy for each polygon
for i in range(len(polygons)):
polygon = polygons.iloc[i]
angles = orientations.loc[edges_subset]
if len(angles) > 1:
freqs = np.histogram(angles, bins=36, range=(0, 360))[0]
freqs = freqs / sum(freqs)
entropy = -sum([freqs[j] * np.log2(freqs[j]) for j in range(len(freqs)) if freqs[j] > 0])
polygon['entropy'] = entropy
else:
polygon['entropy'] = np.nan
Save results to shapefile
polygons.to_file('result.shp')