python - Geoplot 不会绘制 geopandas 对象

Question

我使用 geopandas 导入了威斯康星州各县的 shapefile 以及每个县上次选举的选票差额。我现在尝试使用每个县的投票份额的 Voronoi 曲面分割将威斯康星州划分为多个社区。我想使用 geoplot.voronoi 来执行此操作，但在 shapefile 上调用 geoplot.voronoi 时，geoplot 无法绘制 map 并崩溃数据。

以下代码成功生成了投票份额的 map

import pandas as pd
import matplotlib.pyplot as plt
import geopandas as gp

wi = gp.GeoDataFrame.from_file('./data/shape/Wards_111312.shp')
elec_dat = pd.read_csv('./data/wi_2014_heda.csv')

wi['vrat'] = elec_dat['g2014_SOS_rv']
wi['vdat'] = elec_dat['g2014_SOS_dv']
wi['mr'] = (wi['vdat'] - wi['vrat']) / ((wi['vdat'] + wi['vrat']))
wi['mr'] = wi['mr'].fillna(0)

wi.plot(column = 'mr', cmap='OrRd')

但是，当我尝试使用 geoplot 绘制相同的内容时，我得到一个空白图像(下面的明显空白是图像)。

import geoplot
geoplot.polyplot(wi)

此外，如果我尝试绘制 Voronoi 曲面分割:

ax = geoplot.voronoi(
    wi.sample(1000),
    hue='mr', cmap='Reds', scheme='fisher_jenks',
    clip=wi.geometry,
    linewidth=0)
geoplot.polyplot(wi, ax=ax)

我收到以下错误:

/home/rtse/anaconda3/envs/gerry/lib/python3.6/site-packages/pysal/__init__.py:65: VisibleDeprecationWarning: PySAL's API will be changed on 2018-12-31. The last release made with this API is version 1.14.4. A preview of the next API version is provided in the `pysal` 2.0 prelease candidate. The API changes and a guide on how to change imports is provided at https://pysal.org/about
  ), VisibleDeprecationWarning)

---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-2-5ed5e333efcd> in <module>
      7     hue='mr', cmap='Reds', scheme='fisher_jenks',
      8     clip=wi.geometry,
----> 9     linewidth=0)
     10 geoplot.polyplot(wi, ax=ax)
     11 

~/anaconda3/envs/gerry/lib/python3.6/site-packages/geoplot/geoplot.py in voronoi(df, projection, edgecolor, clip, hue, scheme, k, cmap, categorical, vmin, vmax, legend, legend_kwargs, legend_labels, extent, figsize, ax, **kwargs)
   2126 
   2127     # Finally we draw the features.
-> 2128     geoms = _build_voronoi_polygons(df)
   2129     if projection:
   2130         for color, geom in zip(colors, geoms):

~/anaconda3/envs/gerry/lib/python3.6/site-packages/geoplot/geoplot.py in _build_voronoi_polygons(df)
   2628     """
   2629     from scipy.spatial import Voronoi
-> 2630     geom = np.array(df.geometry.map(lambda p: [p.x, p.y]).tolist())
   2631     vor = Voronoi(geom)
   2632 

~/anaconda3/envs/gerry/lib/python3.6/site-packages/pandas/core/series.py in map(self, arg, na_action)
   2996         """
   2997         new_values = super(Series, self)._map_values(
-> 2998             arg, na_action=na_action)
   2999         return self._constructor(new_values,
   3000                                  index=self.index).__finalize__(self)

~/anaconda3/envs/gerry/lib/python3.6/site-packages/pandas/core/base.py in _map_values(self, mapper, na_action)
   1002 
   1003         # mapper is a function
-> 1004         new_values = map_f(values, mapper)
   1005 
   1006         return new_values

pandas/_libs/src/inference.pyx in pandas._libs.lib.map_infer()

~/anaconda3/envs/gerry/lib/python3.6/site-packages/geoplot/geoplot.py in <lambda>(p)
   2628     """
   2629     from scipy.spatial import Voronoi
-> 2630     geom = np.array(df.geometry.map(lambda p: [p.x, p.y]).tolist())
   2631     vor = Voronoi(geom)
   2632 

AttributeError: 'MultiPolygon' object has no attribute 'x'

我是否缺少在 geoplot 中绘制几何图形所需的步骤？我正在关注this example code ，但他们从 geopandas.datasets 加载数据，而不是提供自己的 shapefile。我做错了什么？

预先感谢您提供的所有帮助!

Answer 1

我刚刚遇到了与此类似的问题，发现我的问题是我的 LAT 和 LON 值向后。 shapely.Point 元组 需要是 (LON,LAT)。

空白图的另一个可能原因是该图根本不是空白的，它只是一个非常大区域的 map 。我认为这对于您的绘图来说不太可能，但您可以通过将具有最小和最大 LON 和 LAT 值的元组传递给 gplt.polyplot() 中的 extent 变量来检查这一点。