在Cartopy地图上绘制shapefile城市边界

Question

我正在尝试使用在here之后并在this example之后获得的shapefile在Cartopy地形图的顶部绘制湾区城市/城镇边界的轮廓。由于某些原因，即使我通过zorder指定边框位于顶部，边框也不会显示。我想念什么吗？

# import functions
import matplotlib.pyplot as plt
import cartopy.io.img_tiles as cimgt
import cartopy.crs as ccrs
from cartopy.io.shapereader import Reader
from cartopy.feature import ShapelyFeature

# Create a Stamen terrain background instance
stamen_terrain = cimgt.Stamen('terrain-background')
fig = plt.figure(figsize = (10, 10))
ax = fig.add_subplot(1, 1, 1, projection=stamen_terrain.crs)

# Set range of map, stipulate zoom level
ax.set_extent([-122.7, -121.5, 37.15, 38.15], crs=ccrs.Geodetic())
ax.add_image(stamen_terrain, 12, zorder = 0)

# Add city borders - not working
filename = r'./shapefile/ba_cities.shp' # from https://earthworks.stanford.edu/catalog/stanford-vj593xs7263
shape_feature = ShapelyFeature(Reader(filename).geometries(), ccrs.PlateCarree(), edgecolor='black')
ax.add_feature(shape_feature, zorder = 1)
plt.show()

Answer 1

正如@ImportanceOfBeingErnest和@swatchai所建议的那样，ShapelyFeature cartopy.feature.ShapelyFeature()中的CRS（坐标参考系统）参数不正确。

在shapefile随附的.xml文件之一中可以找到正确的EPSG（欧洲石油调查组织？）代码：

   <gco:CharacterString>26910</gco:CharacterString>
</code>
<codeSpace>
   <gco:CharacterString>EPSG</gco:CharacterString>

并将其作为ShapelyFeature()中的第二个参数传递，即可获取shapefile正确绘制城市边界：

# Add city borders
filename = r'./shapefile/ba_cities.shp'
shape_feature = ShapelyFeature(Reader(filename).geometries(), ccrs.epsg(26910), 
                               linewidth = 1, facecolor = (1, 1, 1, 0), 
                               edgecolor = (0.5, 0.5, 0.5, 1))
ax.add_feature(shape_feature)
plt.show()