[Python uses shp files for drawing whitening]

The role of albinism

• Reference blog post [matlab uses shp file to make mask whitening file]

Python implementation

• Python uses the shp file to whiten the drawing, without the need to make a mask file, and can efficiently draw areas

import numpy as np
import cartopy.crs as ccrs
import cartopy.feature as cf
import matplotlib.pyplot as plt
import cartopy.io.shapereader as shpreader
from cartopy.mpl.ticker import LatitudeFormatter,LongitudeFormatter
from matplotlib.path import Path
from cartopy.mpl.patch import geos_to_path
plt.rcParams['font.sans-serif']=['KaiTi']
shp_path=r'.\省.shp'
shp_data=shpreader.Reader(shp_path)
fig=plt.figure(figsize=(3,2),dpi=500)
ax1=plt.subplot(121,projection=ccrs.PlateCarree())
ax2=plt.subplot(122,projection=ccrs.PlateCarree())
for i,ax in enumerate([ax1,ax2]):
    ax.add_geometries(shp_data.geometries(),crs=ccrs.PlateCarree(),edgecolor='k',facecolor='none',lw=0.5)
    ax.set_extent([70, 140, 0, 55],crs=ccrs.PlateCarree())
    ax.set_xticks(np.arange(70,140,5))
    ax.set_yticks(np.arange(0,55,5))
    # ax.xaxis.set_major_formatter(LongitudeFormatter())
    # ax.yaxis.set_major_formatter(LatitudeFormatter())
    ax.tick_params(direction='in',labelsize=3,top=True,right=True,length=2,width=0.5)
    if i==0:
            ax.set_title('未白化',fontsize=6)
    else:
            ax.set_title('白化后',fontsize=6)
########定义绘图数据######################
x=np.arange(70, 140, 0.02)
y=np.arange(0, 55, 0.02)
X,Y=np.meshgrid(x,y)
Z=(X-108)**2+(Y-29)**2
#######循环画图#########################
for i,ax in enumerate([ax1,ax2]):
    if i==0:
        ax.contourf(X,Y,Z)
    else:
        ac=ax.contourf(X,Y,Z)
#######获取path#######################
records=shp_data.records()
for record in records:
    if record.attributes["省"] in ["河南省"]:
        path=Path.make_compound_path(*geos_to_path([record.geometry]))
#######白化###########################
for collection in ac.collections:
    collection.set_clip_path(path, transform=ax2.transData)

file_nineline = ".\九段线.shp"
reader_nineline = shpreader.Reader(file_nineline)
ax.add_geometries(reader_nineline.geometries(), crs=ccrs.PlateCarree(), lw=0.5, fc='none')

plt.show()

• Reference: https://mp.weixin.qq.com/s?__biz=MzIxODQxODQ4NQ==&mid=2247484487&idx=1&sn=e654ab7eeeb41a15f816b52b391e93cb&chksm=97eb981da09c110ba06115ed93a4a4450b be84f8b57b90a9819b6b06f801b533c1b002f14223& scene=21