geopandas 地图以国家为中心

如何解决geopandas 地图以国家为中心

我正在 geopandas 上为前苏联绘制数据，但它看起来确实不好看。

我尝试了在 1、2 早期发布的这段代码，但没有增加任何帮助，因此我不仅需要地图，还需要将数据放在上面。而且因为我正在合并“世界”（实际上仅由前苏联国家组成）和“关于“国家”的冠状病毒数据，所以我需要该数据框与原始国家和调整后的多边形。

我的代码的关键点：

url = "https://opendata.arcgis.com/datasets/a21fdb46d23e4ef896f31475217cbb08_1.geojson"
world = gpd.read_file(url)
ex_ussr = ['Ukraine','Belarus','Kyrgyzstan','Azerbaijan','Tajikistan','Armenia','Georgia','Russia','Kazakhstan','Lithuania','Latvia','Estonia','Uzbekistan']
world = world[world['CNTRY_NAME'].isin(ex_ussr)]
df_world = pd.merge(df_covid,world,on='Country')
crs = {'init': 'epsg:4326'}
corona_gpd = gpd.GeoDataFrame(df_world,crs=crs,geometry='geometry')
f,ax = plt.subplots(1,1,figsize=(30,5))
ax = corona_gpd.plot(column='New cases',cmap='rainbow',ax=ax,legend=True,legend_kwds={'label': 'New Cases by Country'})

解决方法

这是一个具有挑战性的问题，我很乐意尝试。以下是一个可运行的代码，它将创建一个具有良好几何形状的 russia 地理数据框 - 几何形状不会在日期变更线上分开。

import numpy as np
import matplotlib.pyplot as plt
import geopandas as gpd

#import cartopy.crs as ccrs
#import cartopy

from shapely.geometry import LineString,MultiPolygon,Polygon
from shapely.ops import split
from shapely.affinity import translate
import geopandas

def shift_geom(shift,gdataframe,plotQ=False):
    # this code is adapted from somewhere found in SO
    # *** will give credit here ***
    shift -= 180
    moved_map = []
    splitted_map = []
    border = LineString([(shift,90),(shift,-90)])

    for row in gdataframe["geometry"]:
        splitted_map.append(split(row,border))
    for element in splitted_map:
        items = list(element)
        for item in items:
            minx,miny,maxx,maxy = item.bounds
            if minx >= shift:
                moved_map.append(translate(item,xoff=-180-shift))
            else:
                moved_map.append(translate(item,xoff=180-shift))

    # got `moved_map` as the moved geometry            
    gdf = geopandas.GeoDataFrame({"geometry": moved_map})
    # can move back to original pos by rerun with -ve shift

    # can change crs here
    if plotQ:
        fig,ax = plt.subplots()
        gdf.plot(ax=ax)
        plt.show()

    return gdf


world = geopandas.read_file(geopandas.datasets.get_path('naturalearth_lowres'))
world = world[['name','continent','geometry','pop_est','gdp_md_est']]

ex_ussr = ['Ukraine','Belarus','Kyrgyzstan','Azerbaijan','Tajikistan','Armenia',\
           'Georgia','Kazakhstan','Lithuania','Latvia','Estonia','Uzbekistan']

# ex_ussr w/o russia
ex_ussr_gdf = world[world['name'].isin(ex_ussr)]
# russia only
russia = world[ world['name']=='Russia' ]

# manipulate russia's geometry
rus_shift_90 = shift_geom(90,russia,False)        # Do not plot
good_geom_rus = shift_geom(-90,rus_shift_90,True) # Plot it

# a plot of new geometry appears

# Create geodataframe with 1 row (Multi-polygon) using this geometry
newrus_gdf = geopandas.GeoDataFrame( { "name": ["Russia"],"new_geometry": [good_geom_rus.geometry.unary_union]},\
                             geometry="new_geometry",crs="EPSG:4326")
# Merge `russia` with `newrus_gdf` to get everything in 1 dataframe
russia_final = russia.merge(right=newrus_gdf,on="name")

# Set the `new_geometry` from `newrus_gdf` as the geometry
russia_final.set_geometry("new_geometry",drop=True,inplace=True)

# plot all ex_ussr together = `russia_final` + `ex_ussr_gdf`
rus_ax = russia_final.plot(color='brown')
ex_ussr_gdf.plot(ax=rus_ax,color="green",ec="black",lw=0.3,alpha=0.75)

编辑

要将 russia_final 添加到 ex_ussr_gdf 并绘制结果，请运行以下代码：-

ex_ussr_gdf = ex_ussr_gdf.append(russia_final,ignore_index=True)
ex_ussr_gdf.plot(color="pink",lw=0.3)