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

# 创建图形和轴，使用 PlateCarree 投影
fig = plt.figure(figsize=(10, 6))
ax = fig.add_subplot(1, 1, 1, projection=ccrs.PlateCarree())

# 添加地图细节
ax.add_feature(cfeature.COASTLINE)
ax.add_feature(cfeature.BORDERS, linestyle=':')
ax.add_feature(cfeature.LAND, facecolor='lightgray')
ax.add_feature(cfeature.OCEAN, facecolor='lightblue')

# 设置地图范围（中国区域）
ax.set_extent([70, 140, 15, 55], crs=ccrs.PlateCarree())

# 定义两个城市的坐标（经度, 纬度）
beijing = (116.4074, 39.9042)
shanghai = (121.4737, 31.2304)

# 绘制连接两点的线
ax.plot([beijing[0], shanghai[0]], [beijing[1], shanghai[1]],
        color='red', linewidth=2, marker='o', transform=ccrs.PlateCarree())

# 添加标注
mid_lon = (beijing[0] + shanghai[0]) / 2
mid_lat = (beijing[1] + shanghai[1]) / 2
ax.text(mid_lon, mid_lat, '航线', transform=ccrs.PlateCarree(),
        fontsize=12, color='darkblue', weight='bold',
        ha='center', va='center', backgroundcolor='white')

# 添加城市标签
ax.text(beijing[0], beijing[1], '北京', transform=ccrs.PlateCarree(),
        fontsize=10, ha='right', va='bottom')
ax.text(shanghai[0], shanghai[1], '上海', transform=ccrs.PlateCarree(),
        fontsize=10, ha='left', va='bottom')

# 显示图
plt.title("地图上的标注线示例")
plt.show()

基本上就这些。根据需求选择静态图还是交互图，cartopy 适合科研绘图，folium 适合网页展示。