Network Graphs using plotly

Dash Python
1

I’m unable to get network graph for a call back in my web app which changes according to slider

Here’s the code
def update_graph(year_value):

    path="C:/Users/ilike/Desktop/aseann.xlsx"
    wb=xl.load_workbook(path)
    countries=wb.sheetnames
    YRA=format(year_value)
    G=nx.Graph()
    pos=nx.spring_layout(G,dim=3)
    for c in countries:
                    ws=wb[c]
                    
                    max_r=ws.max_row
                    max_c=ws.max_column
                    for r in range(4,max_r,3):
                                    yr_ob=ws.cell(row=r,column=1)
                                    yr=yr_ob.value
                                    if yr==YRA:
                                                    for cl in range(2,max_c):
                                                                    cob=ws.cell(row=3,column=cl)
                                                                    cnt=cob.value
                                                                    cov=ws.cell(row=r,column=cl)
                                                                    ov=cov.value
                                                                    if ov!=0 and ov!=None:
                                                                                    G.add_edge(c,cnt)
                                                    
                                                                    else:
                                                                            continue
                                                                            
    



    nx.draw(G,with_labels=1)
    pos=nx.spring_layout(G,dim=3)
    edge_trace=go.Scatter3d(x=[],y=[],z=[],line={'width':0.5,'color':'#888'},hoverinfo='none',mode='lines')
    for edge in G.edges():
            x0,y0,z0=pos.get(edge[0])
            x1,y1,z1=pos.get(edge[1])
            edge_trace['x']+=tuple([x0,x1,None])
            edge_trace['y']+=tuple([y0,y1,None])
            edge_trace['z']+=tuple([z0,z1,None])
    node_trace = go.Scatter3d(x=[], y=[], text=[], mode='markers', hoverinfo='text') 
    for node in G.nodes():
             x,y,z=pos.get(node)
             node_trace['x']+=tuple([x])
             node_trace['y']+=tuple([y])
             node_trace['z']+=tuple([z])
    return{"data":[edge_trace, node_trace],
          "layout": go.Layout(title='Network Graph With Dash', showlegend=False, hovermode='closest',
                              margin={'b': 20, 'l': 5, 'r': 5, 't': 40},
                              xaxis={'showgrid': False, 'zeroline': False, 'showticklabels': False},
                              yaxis={'showgrid': False, 'zeroline': False, 'showticklabels': False})}

if name == ‘main’:

            app.run_server(debug=True)
2

Hi @teja_m19, what is the issue with this app? Are you able to display the figure? Do you get an error? Please provide more details and/or attach the whole app code, ideally hosting your data file somewhere so that we can reproduce.

3

The program should display network graphs when user changes the slider according to the year . But the graph isn’t getting displayed . .
The project file :- https://drive.google.com/drive/folders/1TVXE4n3OV6ZZ3Z1V-5igC22d_UID8y8Z?usp=sharing

where [year_wise.py] is the program for displaying network graphs according to the excel sheet [aseann.xlsx]

and the graph should be displayed in Main File [nx.py] i.e dash file

THANKS

4

@teja_m19

The network isn’t displayed because in node_trace, which should be an instance of go.Scatter3d, z isn’t initialized:

 node_trace = go.Scatter3d(x=[], y=[], text=[], mode='markers', hoverinfo='text')

Usually you should get an error message after this line:
node_trace['z']+=tuple([z])
The right definition of node_trace:

node_trace = go.Scatter3d(x=[], y=[], z=[],text=[], mode='markers', hoverinfo='text')
5

Done but still incomplete. Thanks ! :slight_smile:

6

@teja_m19

I detected the error running this code:

import networkx as nx
import numpy as np
import json
import requests
import plotly.graph_objects as go

content = requests.get("https://raw.githubusercontent.com/plotly/datasets/master/miserables.json")
jdata = json.loads(content.content)


N = len(jdata['nodes'])
L = len(jdata['links'])
E = [(jdata['links'][k]['source'], jdata['links'][k]['target']) for k in range(L)]

V = np.arange(N)

G = nx.Graph()
G.add_nodes_from(V)
G.add_edges_from(E)

pos = nx.spring_layout(G,dim=3)
edge_trace = go.Scatter3d(x=[],y=[],z=[],line={'width':0.5,'color':'#888'},hoverinfo='none',mode='lines')
for edge in G.edges():
    x0,y0,z0=pos.get(edge[0])
    x1,y1,z1=pos.get(edge[1])
    edge_trace['x']+=tuple([x0,x1,None])
    edge_trace['y']+=tuple([y0,y1,None])
    edge_trace['z']+=tuple([z0,z1,None])
node_trace = go.Scatter3d(x=[], y=[], z=[], text=[], mode='markers', hoverinfo='text') 
for node in G.nodes():
    x, y, z=pos.get(node)
    node_trace['x']+=tuple([x])
    node_trace['y']+=tuple([y])
    node_trace['z']+=tuple([z])
#    return{"data":[edge_trace, node_trace],
fig= go.Figure(data=[edge_trace, node_trace])

fig.update_layout(width=800, height=800, title='Network Graph With Dash', showlegend=False, hovermode='closest',
                              margin={'b': 20, 'l': 5, 'r': 5, 't': 40},
                              xaxis={'showgrid': False, 'zeroline': False, 'showticklabels': False},
                              yaxis={'showgrid': False, 'zeroline': False, 'showticklabels': False})

network3d
network3d700×500 45.3 KB

Maybe your data used to define the graph are incomplete or contain nans.

1 Like
7

unable to get edges . I am newly using plot . It doesnt display edges . Thanks for the help