CODEWITHSUNDEEP
pythonpython-2.7matplotlibgraphviznetworkx
JuanPi
JuanPi

Reputation: 781

Networkx: Overlapping edges when visualizing MultiGraph

The following multigraph plots correctly (i.e. parallel edges do not overlap) using graphviz neato to generate a png (as shown in this answer)

import networkx as nx
nx.MultiGraph ([(1,2),(1,2),(1,2),(3,1),(3,2)])
nx.write_dot(Gm,'multi.dot')
!neato -T png multi.dot > multi.png

However using the draw function of Networkx doesn't do the trick

nx.draw_graphviz(Gm,prog='neato')

Is it possible to prevent overlapping edges using the draw methods from Networkx?

Thanks

Upvotes: 16

Views: 16419

Answers (4)

Lee
Lee

Reputation: 31040

You can use matplotlib directly using the node positions you have calculated. 

G=nx.MultiGraph ([(1,2),(1,2),(1,2),(3,1),(3,2)])
pos = nx.random_layout(G)
nx.draw_networkx_nodes(G, pos, node_color = 'r', node_size = 100, alpha = 1)
ax = plt.gca()
for e in G.edges:
    ax.annotate("",
                xy=pos[e[0]], xycoords='data',
                xytext=pos[e[1]], textcoords='data',
                arrowprops=dict(arrowstyle="->", color="0.5",
                                shrinkA=5, shrinkB=5,
                                patchA=None, patchB=None,
                                connectionstyle="arc3,rad=rrr".replace('rrr',str(0.3*e[2])
                                ),
                                ),
                )
plt.axis('off')
plt.show()

enter image description here

Upvotes: 6

AMangipinto
AMangipinto

Reputation: 569

An improvement to the answer above is adding the connectionstyle argument to nx.draw:

import networkx as nx
G = nx.DiGraph()
G.add_nodes_from([0,1])
pos = nx.circular_layout(G)
nx.draw_networkx_nodes(G, pos, connectionstyle='arc3, rad = 0.1', node_color = 'r', node_size = 100, alpha = 1)
nx.draw_networkx_edges(G, pos,connectionstyle='arc3, rad = 0.1', edgelist = [(0,1)], width = 2, alpha = 0.5, edge_color='b')
nx.draw_networkx_edges(G, pos,connectionstyle='arc3, rad = 0.1', edgelist= [(1,0)], width = 1, alpha = 1)
plt.axis('off')
plt.show()

See result here

Upvotes: 5

Sarah Desouky
Sarah Desouky

Reputation: 21

Well I know its probably not what you're looking for, but I was facing a similar problem where I wanted to have a directed graph where the edge between two nodes had a different weight depending on the direction (whether it was going into or out of the node) and the work around I did was I used a different color for each edge and decreased the opacity for one of them so it would show even if they overlap. I only needed two edges between my two nodes so it did the trick for me. 

G = nx.DiGraph()
G.add_nodes_from([0,1])
pos = nx.circular_layout(G)
nx.draw_networkx_nodes(G, pos, node_color = 'r', node_size = 100, alpha = 1)
nx.draw_networkx_edges(G, pos, edgelist = [(0,1)], width = 2, alpha = 0.5, edge_color='b')
nx.draw_networkx_edges(G, pos, edgelist= [(1,0)], width = 1, alpha = 1)
plt.axis('off')
plt.show()

enter image description here

Upvotes: 2

Aric
Aric

Reputation: 25289

Unfortunately not. It is technically possible to do but so far nobody has written the code.

Upvotes: 8

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