Matplotlib geographic maps with CartoPy

December 17, 2020

PROJ.4 / GEOS-based CartoPy downloads and caches shape files as needed, avoiding a large install up front. CartoPy uses shapely and other easily available / automatically & seamlessly installed prereqs.

conda install cartopy

Note the zorder option of Matplotlib elements such as contourf. Higher number zorder is higher priority (on top). See PlotPrecip.py for an example of zorder. An example using CartoPy follows:

import cartopy
import cartopy.feature as cpf
from matplotlib.pyplot import figure, show
import numpy.random as npr


proj = cartopy.crs.PlateCarree()

ax = figure().gca(projection=proj)

ax.add_feature(cpf.LAND)
ax.add_feature(cpf.OCEAN)
ax.add_feature(cpf.COASTLINE)
ax.add_feature(cpf.BORDERS, linestyle=':')
# ax.add_feature(cpf.LAKES,   alpha=0.5)
# ax.add_feature(cpf.RIVERS)

N = 10

lat = (npr.random(N) - 0.5) * 180
lon = (npr.random(N) - 0.5) * 360

ax.scatter(lon, lat, transform=proj)

show()

CartoPy can even make an auroral oval.

Cartopy replaced Matplotlib basemap, which was deprecated in 2017.