底图readshapefile ValueError

Question

我以shapefile格式从US Census下载了地图。它具有我需要的所有必需信息，但由于某种原因，我需要一个特定的地图给我这个错误：

Traceback (most recent call last):
  File "C:/Users/Leb/Desktop/Python/Kaggle/mapp.py", line 17, in <module>
    shp_info = m.readshapefile('gis/cb_2014_us_state_5m', 'states', drawbounds=True)
  File "C:\Program Files\Python 3.5\lib\site-packages\mpl_toolkits\basemap\__init__.py", line 2162, in readshapefile
    raise ValueError('readshapefile can only handle 2D shape types')
ValueError: readshapefile can only handle 2D shape types

更具体地说，these文件集给了我错误。如您所见，我下载了5m分辨率shapefile。

这是我用来执行命令的代码：

import matplotlib.pyplot as plt
from mpl_toolkits.basemap import Basemap as Basemap

m = Basemap(llcrnrlon=-119, llcrnrlat=22, urcrnrlon=-64, urcrnrlat=49,
            projection='lcc', lat_1=33, lat_2=45, lon_0=-95)
shp_info = m.readshapefile('gis/cb_2014_us_state_5m', 'states', drawbounds=True)

问题：

1. 我是否需要通过Fiona进行转换？还是ArcGIS？为了 将其更改为正确的格式。
2. 是否有更好的替代basemap？

Answer 1

问题是这些cb_文件是形状为3D的PolygonZ对象的列表，而readhapefile需要它们是2D Polygon对象，即使Z维度都是0，就像这些cb_*文件的情况一样。你可以convert them by stripping the Z dimension。

我开始使用geopandas作为底图和其他实用程序的包装器，这就是我转换它们的方式：

def convert_3D_2D(geometry):
    '''
    Takes a GeoSeries of Multi/Polygons and returns a list of Multi/Polygons
    '''
    import geopandas as gp
    new_geo = []
    for p in geometry:
        if p.has_z:
            if p.geom_type == 'Polygon':
                lines = [xy[:2] for xy in list(p.exterior.coords)]
                new_p = Polygon(lines)
                new_geo.append(new_p)
            elif p.geom_type == 'MultiPolygon':
                new_multi_p = []
                for ap in p:
                    lines = [xy[:2] for xy in list(ap.exterior.coords)]
                    new_p = Polygon(lines)
                    new_multi_p.append(new_p)
                new_geo.append(MultiPolygon(new_multi_p))
    return new_geo

import geopandas as gp
some_df = gp.from_file('your_cb_file.shp')
some_df.geometry = convert_3D_2D(cbsa.geometry)

使用pip install geopandas安装GeoPandas。我认为应该是它！