Jupyter Snippet CB2nd 02_airports

14.2. Drawing flight routes with NetworkX

import math
import json
import numpy as np
import pandas as pd
import networkx as nx
import cartopy.crs as ccrs
import matplotlib.pyplot as plt
from IPython.display import Image
%matplotlib inline

names = ('airline,airline_id,'
         'source,source_id,'
         'dest,dest_id,'
         'codeshare,stops,equipment').split(',')

routes = pd.read_csv(
    'https://github.com/ipython-books/'
    'cookbook-2nd-data/blob/master/'
    'routes.dat?raw=true',
    names=names,
    header=None)
routes

png

names = ('id,name,city,country,iata,icao,lat,lon,'
         'alt,timezone,dst,tz,type,source').split(',')

airports = pd.read_csv(
    'https://github.com/ipython-books/'
    'cookbook-2nd-data/blob/master/'
    'airports.dat?raw=true',
    header=None,
    names=names,
    index_col=4,
    na_values='\\N')
airports_us = airports[airports['country'] ==
                       'United States']
airports_us

png

routes_us = routes[
    routes['source'].isin(airports_us.index) &
    routes['dest'].isin(airports_us.index)]
routes_us

png

edges = routes_us[['source', 'dest']].values
edges

array([['ADQ', 'KLN'],
       ['KLN', 'KYK'],
       ['BRL', 'ORD'],
       ...,
       ['SOW', 'PHX'],
       ['VIS', 'LAX'],
       ['WRL', 'CYS']], dtype=object)

g = nx.from_edgelist(edges)

len(g.nodes()), len(g.edges())

(546, 2781)

fig, ax = plt.subplots(1, 1, figsize=(6, 6))
nx.draw_networkx(g, ax=ax, node_size=5,
                 font_size=6, alpha=.5,
                 width=.5)
ax.set_axis_off()

png

sg = next(nx.connected_component_subgraphs(g))

fig, ax = plt.subplots(1, 1, figsize=(6, 6))
nx.draw_networkx(sg, ax=ax, with_labels=False,
                 node_size=5, width=.5)
ax.set_axis_off()

png

pos = {airport: (v['lon'], v['lat'])
       for airport, v in
       airports_us.to_dict('index').items()}

deg = nx.degree(sg)
sizes = [5 * deg[iata] for iata in sg.nodes]

altitude = airports_us['alt']
altitude = [altitude[iata] for iata in sg.nodes]

labels = {iata: iata if deg[iata] >= 20 else ''
          for iata in sg.nodes}

# Map projection
crs = ccrs.PlateCarree()
fig, ax = plt.subplots(
    1, 1, figsize=(12, 8),
    subplot_kw=dict(projection=crs))
ax.coastlines()
# Extent of continental US.
ax.set_extent([-128, -62, 20, 50])
nx.draw_networkx(sg, ax=ax,
                 font_size=16,
                 alpha=.5,
                 width=.075,
                 node_size=sizes,
                 labels=labels,
                 pos=pos,
                 node_color=altitude,
                 cmap=plt.cm.autumn)

png