Display a networkx graph on a leaflet map

readme.MD

This gist displays a networkx graph on a leaflet map.

The graph is supplied as a weighted GEXF file, each node is expected to have Latitude and Longitude attributes.

The inputfile (GEXF format graph) and the basename for the outputfile are suplied as command line arguments.

Run as follows:

python plot.py sample.gexf output/spatial-graph

plot.py

import networkx as nx
import numpy as np
import matplotlib as mpl
import matplotlib.pyplot as plt
import mplleaflet
import sys

def main():
    inputfile=sys.argv[1]
    outputfile_base=sys.argv[2]
    # Load GEXF
    g = nx.read_gexf(inputfile)
    # Create node positions
    pos={}
    for i, node in enumerate(g.nodes()):
        print(i, node)
        if ('Latitude' in g.nodes[node].keys() 
                and 'Longitude' in g.nodes[node].keys()):
            lat=g.nodes[node]['Latitude']
            lng=g.nodes[node]['Longitude']
            if not np.isnan(lat) and not np.isnan(lng):
                pos[node]=[g.nodes[node]['Longitude'],g.nodes[node]['Latitude']]
    weights = [g[u][v]['weight'] for u,v in g.edges]
    fig, ax = plt.subplots()
    nx.draw_networkx(g,pos=pos,width=weights)
    path = outputfile_base + '.html'
    mplleaflet.show(fig=ax.figure, path=path)
    # TODO: automate screen capture to image file after suitable wait

if __name__  == '__main__':
    main()

requirements.txt

pandas
networkx
matplotlib
mplleaflet

sample.gexf

<?xml version='1.0' encoding='utf-8'?>
<gexf version="1.2" xmlns="http://www.gexf.net/1.2draft" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.w3.org/2001/XMLSchema-instance">
  <graph defaultedgetype="undirected" mode="static" name="">
    <attributes class="edge" mode="static">
    </attributes>
    <attributes class="node" mode="static">
      <attribute id="0" title="Label" type="string" />
      <attribute id="1" title="Latitude" type="double" />
      <attribute id="2" title="Longitude" type="double" />
      <attribute id="3" title="Caption" type="string" />
    </attributes>
    <meta>
      <creator>NetworkX 2.3</creator>
      <lastmodified>24/03/2020</lastmodified>
    </meta>
    <nodes>
      <node id="0" label="0">
        <attvalues>
          <attvalue for="0" value="K" />
          <attvalue for="1" value="51.483055" />
          <attvalue for="2" value="-0.295703" />
          <attvalue for="3" value="Kew" />
        </attvalues>
      </node>
      <node id="1" label="1">
        <attvalues>
          <attvalue for="0" value="P" />
          <attvalue for="1" value="48.842178" />
          <attvalue for="2" value="2.359820" />
          <attvalue for="3" value="Paris" />
        </attvalues>
      </node>
      <node id="2" label="2">
        <attvalues>
          <attvalue for="0" value="BR" />
          <attvalue for="1" value="50.931194" />
          <attvalue for="2" value="4.319976" />
          <attvalue for="3" value="Meise" />
        </attvalues>
      </node>      
    </nodes>
    <edges>
      <edge id="3" source="0" target="1" weight="10.0">
        <attvalues>
        </attvalues>
      </edge>
      <edge id="4" source="0" target="2" weight="5.0">
        <attvalues>
        </attvalues>
      </edge>
    </edges>
  </graph>
</gexf>