我导出了两组数据:
我想使用networkx库来提取连接给定道路上所有节点的Steiner树。为此,我在jupyter笔记本上编写了以下代码:
import networkx as nx #importing the NetworkX library
Road = nx.read_shp('proj_data/roads/cmbRoads.shp') #Reading Road Data
Base = nx.read_shp('proj_data/bs/bsSnapped.shp') #Reading Terminal Node Data
nodes = list(Base.nodes) #Creating list of terminal nodes
from networkx.algorithms import approximation as ax
st_tree = ax.steinertree.steiner_tree(Road,nodes,weight='length')
所有到Steiner树提取的代码行都已执行,没有任何问题。我收到以下错误消息:
---------------------------------------------------------------------------
NetworkXNotImplemented Traceback (most recent call last)
<ipython-input-5-99884445086e> in <module>
1 from networkx.algorithms import approximation as ax
----> 2 st_tree = ax.steinertree.steiner_tree(Road,nodes,weight='length')
<c:\users\nandula\appdata\local\programs\python\python37\lib\site-packages\decorator.py:decorator-gen-849> in steiner_tree(G, terminal_nodes, weight)
c:\users\nandula\appdata\local\programs\python\python37\lib\site-packages\networkx\utils\decorators.py in _not_implemented_for(not_implement_for_func, *args, **kwargs)
80 raise nx.NetworkXNotImplemented(msg)
81 else:
---> 82 return not_implement_for_func(*args, **kwargs)
83 return _not_implemented_for
84
<c:\users\nandula\appdata\local\programs\python\python37\lib\site-packages\decorator.py:decorator-gen-848> in steiner_tree(G, terminal_nodes, weight)
c:\users\nandula\appdata\local\programs\python\python37\lib\site-packages\networkx\utils\decorators.py in _not_implemented_for(not_implement_for_func, *args, **kwargs)
78 if match:
79 msg = 'not implemented for %s type' % ' '.join(graph_types)
---> 80 raise nx.NetworkXNotImplemented(msg)
81 else:
82 return not_implement_for_func(*args, **kwargs)
NetworkXNotImplemented: not implemented for directed type
任何关于我在这里可能做错了什么的洞察,或者一个我可能完成这件事的创造性的方式(也许是地球帆)都会很有帮助。你知道吗
注意:我没有使用QGIS本身的处理工具箱,因为我需要在CentOS服务器上运行此代码,因为我的个人计算机上没有足够的RAM(数据集非常大)。你知道吗
问题是,从QGIS数据创建的图似乎是有向图,并且该算法仅针对无向图实现。你知道吗
我建议您使用
nx.is_directed
和nx.is_multigraphical
检查您的Road
图形是哪种类型的图形。你知道吗您可以强制转换为无向图
undirected_roads = nx.Graph(Road)
,然后调用算法ax.steinertree.steiner_tree(undirected_roads,nodes,weight='length')
。 但是,根据原始图形的不对称程度,您将丢失一些信息。你知道吗相关问题 更多 >
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