仅在多边形之一OSMNX中获取所有节点

Question

我有一个由两个多边形构成的网络，现在我想确定哪些节点仅位于较大的多边形中。我该怎么办？

代码如下：

import osmnx as ox
import igraph as ig
import matplotlib.pyplot as plt
import pandas as pd
import networkx as nx

city = ['Portugal, Lisbon', 'Portugal, Amadora']
G = ox.graph_from_place(city, network_type='drive', simplify=True)
G_nx = nx.relabel.convert_node_labels_to_integers(G)
nodes, edges = ox.graph_to_gdfs(G_nx, nodes=True, edges=True)

以下是多边形：

较小的多边形是Amadora，另一个是里斯本

Answer 1

您正在寻找within空间运算。这种操作是空间分析的基础，因此，我鼓励您仔细阅读所用工具的文档，以了解其基本概念和用法。如果使用OSMnx，它将包括networkx（用于网络分析）和geopandas（用于空间分析）。例如，在geopandas文档中详细介绍了within方法并给出了用法示例。

import osmnx as ox
ox.config(use_cache=True, log_console=True)

cities = ox.geocode_to_gdf(['Portugal, Lisbon', 'Portugal, Amadora'])
whole_polygon = cities.unary_union #unary union of both geometries
one_polygon = cities['geometry'].iloc[0] #geometry of just lisbon

G = ox.graph_from_polygon(whole_polygon, network_type='drive', simplify=True)
print(len(G)) #12811

# which nodes are within one_polygon?
nodes = ox.graph_to_gdfs(G, edges=False)
nodes_in_polygon = nodes[nodes.within(one_polygon)]
print(len(nodes_in_polygon)) #9734