Question

我无法使用以下代码。无论出于何种原因，GeoPandas * .plot（）都不起作用，但我想在一些简单的图中使用Pandas和GeoPandas。

我一直在尝试从GeoPandas获取Shapely对象并将它们绘制在Basemap上。问题是多边形不会绘制。我从GeoPandas.geometry迭代它们，将它们添加到轴集合，然后使用plot（） - 无济于事。底图似乎工作正常，代码没有给出任何错误，但多边形 - 县 - 没有出现......

感谢您的帮助！

import geopandas as gpd
from descartes import PolygonPatch
import matplotlib as mpl
import mpl_toolkits.basemap as base
import matplotlib.pyplot as plt

counties_file = r'C:\Users\...\UScounties\UScounties.shp'
counties = gpd.read_file(counties_file)

#new plot
fig = plt.figure(figsize=(5,5),dpi=300)
#ax = fig.add_subplot(111)
ax = ax = plt.gca()

minx, miny, maxx, maxy = counties.total_bounds

#map
m = base.Basemap(llcrnrlon=minx, llcrnrlat=miny,
             urcrnrlon=maxx, urcrnrlat=maxy,
             resolution='h', area_thresh=100000,
             projection='merc')

patches = []

#add polygons
for poly in counties.geometry:
    #deal with single polygons and multipolygons
    if poly.geom_type == 'Polygon':
        p = PolygonPatch(poly, facecolor='blue', alpha=1)
        #plt.gca().add_patch(p)
        #ax.add_patch(p)
        patches.append(p)

    elif poly.geom_type == 'MultiPolygon':
        for single in poly:
            q = PolygonPatch(single,facecolor='red', alpha=1)
            #ax.add_patch(p)
            patches.append(q)

m.drawcoastlines(linewidth=.1)
m.fillcontinents()
m.drawcountries(linewidth=.25,linestyle='solid')
m.drawstates(linewidth=.25,linestyle='dotted')
m.drawmapboundary(fill_color='white')

ax.add_collection(mpl.collections.PatchCollection(patches, match_original=True))
ax.plot()

plt.show()

Answer 1

检查shapefile是否在正确的投影系统中。底图目前设置为墨卡托投影。之后它对我有用。

使用匀称多边形进行映射

1 个答案: