Matplotlib Mollweide/Hammer projection: region of interest only

问题

I was wondering if there's a way to only show the region of interest from a plot based on Mollweide/Hammer projection in basemap (matplotlib).

I am trying to set the plot-bounds roughly to the Pacific plate, as in the link below. However, the set_xlim and set_ylim functions do not seem to have any effect. Thanks in advance for any guidance.

http://geology.gsapubs.org/content/29/8/695/F1.large.jpg

回答1:

From the documentation, both Hammer and Mollweide projections don't allow this as they print out entire world maps. Here's some code using Polyconic projection, but it is bounded by straight lines. The trick here is to define the corner longitude and latitudes on creation.

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

my_map = Basemap(projection='poly', lat_0=0, lon_0=-160,
    resolution = 'h', area_thresh = 0.1,
    llcrnrlon=140, llcrnrlat=-60,
    urcrnrlon=-100, urcrnrlat=60)

plt.figure(figsize=(16,12))

my_map.drawcoastlines()
my_map.drawcountries()
my_map.fillcontinents(color='coral', lake_color='aqua')
my_map.drawmapboundary(fill_color='aqua')

my_map.drawmeridians(np.arange(0, 360, 20))
my_map.drawparallels(np.arange(-90, 90, 10))

plt.show()

Result:

Note that this effectively shows less area than the one in the picture you provided.

来源：https://stackoverflow.com/questions/31176169/matplotlib-mollweide-hammer-projection-region-of-interest-only