用cartopy在正交投影中绘制圆

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

fig = plt.figure(figsize=(10, 6))
ax = plt.axes(projection=ccrs.Orthographic(central_longitude=0, central_latitude=0))
ax.set_global()
ax.coastlines()
ax.add_feature(cfeature.LAND)
ax.add_feature(cfeature.OCEAN)

lon = 0  # 圆心经度
lat = 0  # 圆心纬度
radius = 30  # 圆的半径

circle = plt.Circle((lon, lat), radius, transform=ccrs.PlateCarree(), edgecolor='red', facecolor='none')
ax.add_patch(circle)

plt.show()