plot.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
import os
import dash
import dash_core_components as dcc
import dash_html_components as html
import networkx as nx
import plotly.graph_objs as go
from app import app

if 'DYNO' in os.environ:
    app_name = os.environ['DASH_APP_NAME']
else:
    app_name = 'dash-networkplot'

layout = html.Div([
    html.Div([html.H1("Network Graph")], className="row", style={'textAlign': "center"}),
    html.Div([dcc.Graph(id="my-graph", )]),
    html.Div([html.Span("Slide to change No of nodes", style={"text-align": "center", 'padding': 10}, className="row"),
              dcc.Slider(id="nodes", min=5, max=50, value=30, step=2, updatemode="drag",
                         marks={5: "5", 10: "10", 20: "20", 30: "30", 40: "40", 50: "50"}, className="row")],
             style={"display": "block", "margin-left": "auto", "margin-right": "auto", "width": "40%", "padding": 20})
], className="container")


@app.callback(
    dash.dependencies.Output("my-graph", "figure"),
    [dash.dependencies.Input("nodes", "value")])
def update_graph(n):
    G = nx.random_geometric_graph(n, 0.15)
    pos = nx.get_node_attributes(G, 'pos')
    dmin = 1
    ncenter = 0
    for n in pos:
        x, y = pos[n]
        d = (x - 0.5) ** 2 + (y - 0.5) ** 2
        if d < dmin:
            ncenter = n
            dmin = d
    edge_trace = go.Scatter(x=[], y=[], line={'width': 0.5, 'color': '#888'}, hoverinfo='none', mode='lines')
    for edge in G.edges():
        x0, y0 = G.node[edge[0]]['pos']
        x1, y1 = G.node[edge[1]]['pos']
        edge_trace['x'] += tuple([x0, x1, None])
        edge_trace['y'] += tuple([y0, y1, None])
    node_trace = go.Scatter(x=[], y=[], text=[], mode='markers', hoverinfo='text',
                            marker={'showscale': True, 'colorscale': 'Jet', 'reversescale': True, 'color': [],
                                    'size': 10,
                                    'colorbar': {'thickness': 10, 'title': 'No of Connections', 'xanchor': 'left',
                                                 'titleside': 'right'},
                                    'line': {'width': 2}})
    for node in G.nodes():
        x, y = G.node[node]['pos']
        node_trace['x'] += tuple([x])
        node_trace['y'] += tuple([y])
    p = nx.single_source_shortest_path_length(G, ncenter)
    for node, adjacencies in enumerate(G.adjacency()):
        node_trace['marker']['color'] += tuple([len(adjacencies[1])])
        node_info = 'Number of connections: ' + str(len(adjacencies[1]))
        node_trace['text'] += tuple([node_info])
    figure = {"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})}
    return figure