图表中边缘标签的正确位置

Question

import numpy as np
import networkx as nx
import matplotlib.pyplot as plt
%matplotlib inline

a = np.reshape(np.random.random_integers(0,1,size=25),(5,5)) # random 5,5 numpy-array
np.fill_diagonal(a,0)   # remove self-loops                                     
print "np-array: \n" + str(a)

D = nx.DiGraph(a)      # create directional graph from numpy array
weighted_edges = dict(zip(D.edges(),np.random.randint(1,10,size=len(D.edges())))) # assign random weights to each edge
edge_tuple_list =  [(key[0],key[1],value) for key,value in zip(weighted_edges.keys(),weighted_edges.values())] 
D.add_weighted_edges_from(edge_tuple_list) #convert to list of edge tuples and add to the graph

nx.draw(D,with_labels=True,pos=nx.spring_layout(D),node_size=700) #draw the graph
nx.draw_networkx_edge_labels(D,pos=nx.spring_layout(D),edge_labels=nx.get_edge_attributes(D,'weight')) #add edge labels

生成下图。如何修正边标签的位置？

Answer 1

你的问题是，当你调用 pos=nx.spring_layout(G) 时，它会重新计算 pos，它从随机位置开始，然后迭代更新它们。最终结果不是唯一的——根据初始值，结果可能大不相同。所以你第一次绘制网络时它计算了一些位置，但是当你放置边缘标签时它计算了新位置。

所以你想创建一个 pos 字典，它将始终保存相同的位置。我只更改了下面代码的最后 3 行。

import numpy as np
import networkx as nx
import matplotlib.pyplot as plt
%matplotlib inline

a = np.reshape(np.random.random_integers(0,1,size=25),(5,5)) # random 5,5 numpy-array
np.fill_diagonal(a,0)   # remove self-loops                                     
print "np-array: \n" + str(a)

D = nx.DiGraph(a)      # create directional graph from numpy array
weighted_edges = dict(zip(D.edges(),np.random.randint(1,10,size=len(D.edges())))) # assign random weights to each edge
edge_tuple_list =  [(key[0],key[1],value) for key,value in zip(weighted_edges.keys(),weighted_edges.values())] 
D.add_weighted_edges_from(edge_tuple_list) #convert to list of edge tuples and add to the graph

pos = nx.spring_layout(D) # <---this line is new.  the pos here replaces nx.spring_layout below.
nx.draw(D, pos=pos, with_labels=True, node_size=700) #draw the graph
nx.draw_networkx_edge_labels(D, pos=pos, edge_labels=nx.get_edge_attributes(D,'weight')) #add edge labels

图表中边缘标签的正确位置

Correct position of edge labels in a graph plot

python

matplotlib

networkx