import matplotlib.pyplot as plt
import numpy as np
from mpl_toolkits.basemap import Basemap

outfile = r'E:\wrong.tif'

# read in data on lat/lon grid.
hgt = np.loadtxt(r'E:\tmp\basemap\500hgtdata.gz')
lons = np.loadtxt(r'E:\tmp\basemap\500hgtlons.gz')
lats = np.loadtxt(r'E:\tmp\basemap\500hgtlats.gz')
lons, lats = np.meshgrid(lons, lats)

mnh = Basemap(lon_0=-105, boundinglat=20.,
              resolution='c', area_thresh=10000., projection='nplaea')
xnh, ynh = mnh(lons, lats)
CS = mnh.contour(xnh, ynh, hgt, 15, linewidths=0.5, colors='k')
CS = mnh.contourf(xnh, ynh, hgt, 15, cmap=plt.cm.Spectral)

mnh.drawcoastlines(linewidth=0.5)
delat = 30.
circles = np.arange(0., 90., delat).tolist() + \
          np.arange(-delat, -90, -delat).tolist()
mnh.drawparallels(circles, labels=[1, 0, 0, 0])
delon = 45.
meridians = np.arange(0, 360, delon)
mnh.drawmeridians(meridians, labels=[1, 0, 0, 1])
plt.title('NH 500 hPa Height (cm.Spectral)')

# colorbar on bottom.
mnh.colorbar(pad='5%')
plt.savefig(outfile, dpi=300, bbox_inches='tight')  # wrong
# plt.savefig(outfile, dpi=300) # right
plt.show()