形状在更改CCRS后消失。

Question

除了another Q&A，我正在绘制地球上的非洲大陆各国的地图：

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

import geopandas as gpd

world = gpd.read_file(gpd.datasets.get_path('naturalearth_lowres'))
africa = world[(world['continent'] == 'Africa')]

latlon_proj = ccrs.PlateCarree()
axis_proj = ccrs.Mollweide()

ax = plt.axes(projection=axis_proj)
ax.stock_img()

for ea in africa['geometry']:
    
    feat = cartopy.feature.ShapelyFeature(
        [ea],
        latlon_proj,
        facecolor="lime",
        edgecolor='black',
        lw=0.2
        )
    
    ax.add_feature(feat)

plt.show()

​

​

然而，当我把latlon_proj和axis_proj改成ccrs.Orthographic()时，非洲大陆消失了：

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

import geopandas as gpd

world = gpd.read_file(gpd.datasets.get_path('naturalearth_lowres'))
africa = world[(world['continent'] == 'Africa')]

latlon_proj = ccrs.Orthographic()
axis_proj = ccrs.Orthographic()

ax = plt.axes(projection=axis_proj)
ax.stock_img()

for ea in africa['geometry']:
    
    feat = cartopy.feature.ShapelyFeature(
        [ea],
        latlon_proj,
        facecolor="lime",
        edgecolor='black',
        lw=0.2
        )
    
    ax.add_feature(feat)

plt.show()

​

​

我怎样才能保持非洲大陆在改变CCRS的时候？

Answer 1

在代码中使用CRS是错误的。这是它的正确版本。

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

import geopandas as gpd

world = gpd.read_file(gpd.datasets.get_path('naturalearth_lowres'))
africa = world[(world['continent'] == 'Africa')]

latlon_proj = ccrs.PlateCarree()  ## The correct CRS
axis_proj = ccrs.Orthographic()

ax = plt.axes(projection=axis_proj)
ax.stock_img()

for ea in africa['geometry']:

    feat = cartopy.feature.ShapelyFeature(
        [ea],
        latlon_proj,
        facecolor="lime",
        edgecolor='black',
        lw=0.2
        )

    ax.add_feature(feat)

plt.show()

​

​