Python Netgraph Interactive Labels

Question

I am trying to create an interactive plot using netgraph and networkx.

I would like the plot to allow movement of the nodes and as the nodes move, the edges and edge_labels will also dynamically update.

Moving the nodes was addressed by the author of netgraph here . Now when I make a simpler plot and try to label an edge, the label stays static, and is sometimes not even on an edge.

It seems like handling edge_positions similar to node_positions on the last two lines should at least address the label not moving. Why the label isn't anchored to a particular edge is still puzzling. Does anyone know if the desired effect is achievable?

Here is a snip before moving anything:

Here is a snip after moving the bottom-right node to the top left:

Here is my current code:

   
import matplotlib.pyplot as plt
import networkx as nx
import netgraph # pip install netgraph

#Graph creation:
G=nx.Graph(type="")

for i in range(6):
     G.add_node(i,shape="o")

#Changing shape for two nodes
G.nodes[1]['shape'] = "v"
G.nodes[5]['shape'] = "v"

#Add edges
G.add_edge(1,2)
G.add_edge(4,5)
G.add_edge(0,4)
G.add_edge(2,3)
G.add_edge(2,4)

labs={(1,2):"1 to 2"}

nx.draw_networkx_edge_labels(G, pos=nx.spring_layout(G),edge_labels=labs)
#Get node shapes
node_shapes = nx.get_node_attributes(G,"shape")


# Create an interactive plot.
# NOTE: you must retain a reference to the object instance!
# Otherwise the whole thing will be garbage collected after the initial draw
# and you won't be able to move the plot elements around.

pos = nx.layout.spring_layout(G)

######## drag nodes around #########

# To access the new node positions:
plot_instance =   netgraph.InteractiveGraph(G, node_shape=node_shapes, node_positions=pos, edge_positions=pos)


node_positions = plot_instance.node_positions
edge_positions = plot_instance.edge_positions

Since I don't have `netgraph` installed, only as comment: does `netgraph.InteractiveGraph(G, node_shape=node_shapes, node_positions=pos, edge_positions=pos, edge_labels=labs)` fixes your issue? — Sparky05, Oct 08 '20 at 12:40
I had to delete: nx.draw_networkx_edge_labels(G, pos=nx.spring_layout(G),edge_labels=labs) and made the suggested change to this line: netgraph.InteractiveGraph(G, node_shape=node_shapes, node_positions=pos, edge_positions=pos, edge_labels=labs) This now gives me edge_labels that follow the edges. Thanks @Sparky05. Now, how do I give you credit for the answer? — Michael Bernico, Oct 08 '20 at 16:49
Wonderful that it worked :) I've now simply created a full answer, which you can accept and upvote, if you like. — Sparky05, Oct 09 '20 at 10:28

score 2 · Accepted Answer · answered Oct 09 '20 at 10:27

To have it as formal answer, you need to add to the InteractiveGraph object the information that you want to draw (and move) the edge labels, i.e. the following

netgraph.InteractiveGraph(G, 
                          node_shape=node_shapes, 
                          node_positions=pos, 
                          edge_positions=pos, 
                          edge_labels=labs)

(With emphasis on the last parameter)

As you already, noticed then you don't need the call of nx.draw_networkx_edge_labels.

Python Netgraph Interactive Labels

1 Answers1