Generating a density map using Python
In this section, we generate a (human) density map of the United States, where each state is color coded based on its relative population density.
How to do it...
We can use the script:
%matplotlib inline
import matplotlib.pyplot as plt
from mpl_toolkits.basemap import Basemap
from matplotlib.patches import Polygon
import pandas as pd
import numpy as np
import matplotlib
# create the map
map = Basemap(llcrnrlon=-119,llcrnrlat=22,urcrnrlon=-64,urcrnrlat=49,
projection='lcc',lat_1=33,lat_2=45,lon_0=-95)# load the shapefile, use the name 'states'
# download from https://github.com/matplotlib/basemap/tree/master/examples/st99_d00.dbf,shx,shp
map.readshapefile('st99_d00', name='states', drawbounds=True)
# collect the state names from the shapefile attributes so we can
# look up the shape obect for a state by it's name
state_names = []
for shape_dict in map.states_info:
state_names.append(shape_dict['NAME'])
ax = plt.gca() # get current axes instance
...
