Script to show problems using the cartopy ocean feature to mask out the ocean

ocean_mask.py

import numpy as np
import matplotlib.pyplot as plt
import matplotlib.colors as mpc
import matplotlib as mpl
import cartopy.crs as ccrs
import cartopy.feature as cpf
from cartopy.mpl.gridliner import LONGITUDE_FORMATTER, LATITUDE_FORMATTER

# set the size limits

yrg = 2160
xrg = 4320

# make an array

image = np.arange((yrg*xrg)).reshape((yrg, xrg))

# Setup the figure
fig, ax = plt.subplots(1, 1, figsize=(12,9), 
    subplot_kw={'projection': ccrs.PlateCarree()})

ax.set_global()

# make the map
im = ax.imshow(image, extent=[-180, 180, 90, -90])

ax.add_feature(cpf.OCEAN, facecolor="w", alpha=1, zorder=100)
ax.add_feature(cpf.COASTLINE, zorder=101)   
ax.add_feature(cpf.BORDERS, linestyle='--', zorder=102)
ax.add_feature(cpf.LAKES, alpha=0.5, zorder=103)
ax.add_feature(cpf.RIVERS, zorder=104)

print(
    '''\n
    If the oceans are white, then the script is 
    working as designed, if not then not'''
    )

plt.show()

print("Proof that the add_feature is actually working \n")

fig, ax = plt.subplots(1, 1, figsize=(12,9), 
    subplot_kw={'projection': ccrs.PlateCarree()})

ax.set_global()
ax.add_feature(cpf.OCEAN, facecolor="r")
ax.add_feature(cpf.COASTLINE)   
ax.add_feature(cpf.BORDERS, linestyle='--')
ax.add_feature(cpf.LAKES, alpha=0.5)
ax.add_feature(cpf.RIVERS)

print(
    '''If the oceans red then the ocean feature was added'''
    )

plt.show()