Adding Labels to a Shapefile Map - matplotlib

Question

I have a shapefile that maps the world to sales territories. The shapefile records lists the sales territory code and name. I would like to be able to add the territory code in the center of the region, but to do using ax.text, I need the center point of the region. Any ideas how to do this?
import matplotlib.pyplot as plt
import pandas as pd
import numpy as np
import shapefile
from mpl_toolkits.basemap import Basemap as Basemap
from matplotlib.colors import rgb2hex, Normalize
from matplotlib.patches import Polygon
from matplotlib.colorbar import ColorbarBase
from matplotlib.collections import PatchCollection
plt.rcParams['figure.figsize'] = [16,12]
fig = plt.figure()
m = Basemap(llcrnrlon=-121,llcrnrlat=20,urcrnrlon=-62,urcrnrlat=51,
projection='lcc',lat_1=32,lat_2=45,lon_0=-95)
shp_info = m.readshapefile('world_countries_boundary_file_world_2002','countries',drawbounds=True)
sf = shapefile.Reader('territory_map') # Custom file mapping out territories
recs = sf.records()
shapes = sf.shapes()
Nshp = len(shapes)
colors={}
territory_codes=[]
cmap = plt.cm.RdYlGn
# details is a pandas datafile with column "DELTA" that has data to plot
vmin = details.DELTA.min()
vmax = details.DELTA.max()
norm = Normalize(vmin=vmin, vmax=vmax)
for index,row in details.iterrows():
colors[row['TERRITORY_CODE']] = cmap((row['DELTA']-vmin)/(vmax-vmin))[:3]
territory_codes.append(row['TERRITORY_CODE'])
ax = fig.add_subplot(111)
for nshp in range(Nshp):
ptchs = []
pts = np.array((shapes[nshp].points))
prt = shapes[nshp].parts
par = list(prt) + [pts.shape[0]]
for pij in range(len(prt)):
ptchs.append(Polygon(pts[par[pij]:par[pij+1]]))
try:
color = rgb2hex(colors[recs[nshp][0]])
except:
color = 'w' # If no data, leave white (blank)
ax.add_collection(PatchCollection(ptchs, facecolor=color, edgecolor='b', linewidths=.7))
x, y = # Coordinates that are center of region
ax.text(x, y, recs[nshp][0]) # <---- this would be the text to add
# Add colorbar
ax_c = fig.add_axes([0.1, 0.1, 0.8, 0.02])
cb = ColorbarBase(ax_c,cmap=cmap,norm=norm,orientation='horizontal')
cb.ax.set_xlabel('Daily Change, USD')
#Set view to United States
ax.set_xlim(-150,-40)
ax.set_ylim(15,70)
plt.show()
Resulting Map of Code without Territory Names

Answer 1

you're probably looking to take the mean of all the x coordinates and the mean of all the y coordinates of your polygon shape.
I can't test this but it could look something like this:
x,y = pts[0].mean(), pts[1].mean()
or this:
x,y = pts[:,0].mean(), pts[:,1].mean()
depending on the dimensions of your numpy array.