GeoPandas 地图：以国家/地区为中心（并在 180 度经度处加入其分割几何图形）

Question

我正在尝试使用一些自定义 shapefile 绘制俄罗斯等值线图，它目前看起来真的很尴尬。有没有什么办法可以让地图以国家为中心，这样它就不会分成两部分（也许可以放大一点）？

Answer 1

可以根据需要操纵某个国家的几何形状并获得更好的情节。这是一个可运行的代码及其输出图。

import matplotlib.pyplot as plt
import geopandas as gpd
from shapely.geometry import LineString
from shapely.ops import split
from shapely.affinity import translate

def shift_geom(shift, gdataframe, plotQ=False):
    # this code is adapted from answer found in SO
    # will be credited here: ???
    shift -= 180
    moved_geom = []
    splitted_geom = []
    border = LineString([(shift,90),(shift,-90)])

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

    # got `moved_geom` as the moved geometry            
    moved_geom_gdf = gpd.GeoDataFrame({"geometry": moved_geom})

    # can change crs here
    if plotQ:
        fig1, ax1 = plt.subplots(figsize=[8,6])
        moved_geom_gdf.plot(ax=ax1)
        plt.show()

    return moved_geom_gdf

# take the `lowres` data for use
# you can use your own geodataframe here
world = gpd.read_file(gpd.datasets.get_path('naturalearth_lowres'))
# select Russia only
russia = world[world['iso_a3']=="RUS"]
# shift geometry of Russia
new_rus = shift_geom(90, russia, False)
# restore the geometry to original geo-location
# ... geometry now in 1 piece
# ... option True --> make a plot
_ = shift_geom(-90, new_rus, True)

输出图：

GeoPandas 地图：以国家/地区为中心（并在 180 度经度处加入其分割几何图形）

GeoPandas map: Centering the country on the plot (and joining its split geometries at 180 degrees longitude)

python

shapely

geopandas

choropleth