一个 Shapely MultiLinestring 在 Pyplot 中显示为一个 MultiPolygon

Question

目标： 在同一个 pyplot 图上绘制 MultiPolygon（土地）和 MultiLinestring（河流）。将大地染成白色。

问题： 似乎 MultiLinestring 显示为通过自动关闭其所有 Linestring 以使其成为多边形而构建的 MultiPolygon

Telltale：在将 MultiPolygon 着色为白色时，它不会为由 MultiLinestring 中的 Linestrings 制成的多边形着色

这是可复制的代码：

import matplotlib.pyplot as plt
import cartopy.crs as ccrs
import cartopy.io.shapereader as shpreader
from cartopy.feature import ShapelyFeature

# creates a map
map_projection = ccrs.PlateCarree(central_longitude=0.0, globe=None)
map_figure = plt.figure()
map_subplot = plt.axes(projection=map_projection)
# limits the display bounds of the map
map_subplot.set_extent((5.2, 31.4, 35, 54.3), crs=map_projection)

# adding land from a local shp (source : Natural Earth website)
# facecolor = white
landshpfilename = "Central Europe _ lands minus lakes.shp"
landshapereader = shpreader.Reader(landshpfilename)
landshape_feature = ShapelyFeature(landshapereader.geometries(), map_projection, facecolor='white',edgecolor='black')
map_subplot.add_feature(landshape_feature)

# adding large river from a local shp (source : Natural Earth website)
# edgecolor = blue
largeriversshpfilename = "Central Europe _ large rivers minus lakes.shp"
largeriversshapereader = shpreader.Reader(largeriversshpfilename)
largeriversshape_feature = ShapelyFeature(largeriversshapereader.geometries(), map_projection,edgecolor='blue')
map_subplot.add_feature(largeriversshape_feature)

# verifying the geom_type of the first objects in the shapefiles
# putting it as a title
land_geom_type_text = ' '.join(['lands geom_type :',next(landshape_feature.geometries()).geom_type])
river_geom_type_text = ' '.join(['rivers geom_type :',next(largeriversshape_feature.geometries()).geom_type])
map_figure.suptitle('\n'.join([land_geom_type_text,river_geom_type_text]))

plt.show()

结果如下： rendered map

问题：如何解决？

Answer 1

设置 facecolor='none' 将阻止 matplotlib 填充生成的底层路径。一个快速重现的案例：

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


ax = plt.axes(projection=ccrs.PlateCarree())

# Create a feature for States/Admin 1 regions at 1:50m from Natural Earth
states_provinces = cfeature.NaturalEarthFeature(
    category='physical',
    name='rivers_lake_centerlines',
    scale='110m',
    )

ax.add_feature(states_provinces, edgecolor='gray', linewidth=5)
ax.coastlines()

保持其他一切不变，但将特征构造更改为不设置面部颜色会产生所需的结果：

states_provinces = cfeature.NaturalEarthFeature(
    category='physical',
    name='rivers_lake_centerlines',
    scale='110m',
    facecolor='none'
    )