import matplotlib.pyplot as plt
import cartopy.crs as ccrs

fig = plt.figure()
ax = fig.add_subplot(projection=Robinson())
img = ax.imshow(extent=[])
ax.set_extent([-180,180,-60,90], crs=ccrs.PlateCarree())
ax.coastlines(linewidth=0.5)
fig.colorbar(img, aspect=50, pad=0.08, shrink=0.8, orientation='horizontal')