使用底图和 Pandas 的 AssertionError

Question

我正在尝试按照此处的教程进行操作：

http://nbviewer.ipython.org/github/ehmatthes/intro_programming/blob/master/notebooks/visualization_earthquakes.ipynb#install_standard

但是，我使用 pandas 而不是 python 的内置 csv 模块。我的代码如下：

import pandas as pd
eq_data = pd.read_csv('earthquake_data.csv')
map2 = Basemap(projection='robin'
               , resolution='l'
               , area_thresh=1000.0
               , lat_0=0
               , lon_0=0)

map2.drawcoastlines()
map2.drawcountries()
map2.fillcontinents(color = 'gray')
map2.drawmapboundary()
map2.drawmeridians(np.arange(0, 360, 30))
map2.drawparallels(np.arange(-90, 90, 30))

x,y = map2(eq_data['longitude'].values, eq_data['latitude'].values)

map2.plot(x,y, marker='0', markercolor='red', markersize=6)

这会产生 AssertionError 但没有描述：

AssertionError                            Traceback (most recent call last)
<ipython-input-64-d3426e1f175d> in <module>()
     14 x,y = map2(range(20), range(20))#eq_data['longitude'].values, eq_data['latitude'].values)
     15 
---> 16 map2.plot(x,y, marker='0', markercolor='red', markersize=6)

c:\Python27\lib\site-packages\mpl_toolkits\basemap\__init__.pyc in with_transform(self, x, y, *args, **kwargs)
    540             # convert lat/lon coords to map projection coords.
    541             x, y = self(x,y)
--> 542         return plotfunc(self,x,y,*args,**kwargs)
    543     return with_transform
    544 

c:\Python27\lib\site-packages\mpl_toolkits\basemap\__init__.pyc in plot(self, *args, **kwargs)
   3263             ax.hold(h)
   3264         try:
-> 3265             ret =  ax.plot(*args, **kwargs)
   3266         except:
   3267             ax.hold(b)

c:\Python27\lib\site-packages\matplotlib\axes.pyc in plot(self, *args, **kwargs)
   4135         lines = []
   4136 
-> 4137         for line in self._get_lines(*args, **kwargs):
   4138             self.add_line(line)
   4139             lines.append(line)

c:\Python27\lib\site-packages\matplotlib\axes.pyc in _grab_next_args(self, *args, **kwargs)
    315                 return
    316             if len(remaining) <= 3:
--> 317                 for seg in self._plot_args(remaining, kwargs):
    318                     yield seg
    319                 return

c:\Python27\lib\site-packages\matplotlib\axes.pyc in _plot_args(self, tup, kwargs)
    303         ncx, ncy = x.shape[1], y.shape[1]
    304         for j in xrange(max(ncx, ncy)):
--> 305             seg = func(x[:, j % ncx], y[:, j % ncy], kw, kwargs)
    306             ret.append(seg)
    307         return ret

c:\Python27\lib\site-packages\matplotlib\axes.pyc in _makeline(self, x, y, kw, kwargs)
    255                             **kw
    256                             )
--> 257         self.set_lineprops(seg, **kwargs)
    258         return seg
    259 

c:\Python27\lib\site-packages\matplotlib\axes.pyc in set_lineprops(self, line, **kwargs)
    198                 raise TypeError('There is no line property "%s"' % key)
    199             func = getattr(line, funcName)
--> 200             func(val)
    201 
    202     def set_patchprops(self, fill_poly, **kwargs):

c:\Python27\lib\site-packages\matplotlib\lines.pyc in set_marker(self, marker)
    851 
    852         """
--> 853         self._marker.set_marker(marker)
    854 
    855     def set_markeredgecolor(self, ec):

c:\Python27\lib\site-packages\matplotlib\markers.pyc in set_marker(self, marker)
    231         else:
    232             try:
--> 233                 Path(marker)
    234                 self._marker_function = self._set_vertices
    235             except ValueError:

c:\Python27\lib\site-packages\matplotlib\path.pyc in __init__(self, vertices, codes, _interpolation_steps, closed, readonly)
    145             codes[-1] = self.CLOSEPOLY
    146 
--> 147         assert vertices.ndim == 2
    148         assert vertices.shape[1] == 2
    149 

AssertionError:

我认为我遇到了问题，因为 pandas 的更新不再允许像您以前那样传递系列，如下所述：

Runtime error using python basemap and pyproj?

但是如您所见，我为此调整了代码，但并没有解决问题。至此我迷路了。

我在 windows 服务器 2012 x64 上使用 Python 2.7.6、pandas 0.15.2 和底图 1.0.7。

Answer 1

我的代码有两个问题。首先，map2 对象的绘图函数是从 matplotlib 继承的。因此 marker 属性不能是 '0' 它需要是 'o'。此外，没有 markercolor 属性。它被称为color。下面的代码应该可以工作。

import pandas as pd
eq_data = pd.read_csv('earthquake_data.csv')
map2 = Basemap(projection='robin'
               , resolution='l'
               , area_thresh=1000.0
               , lat_0=0
               , lon_0=0)

map2.drawcoastlines()
map2.drawcountries()
map2.fillcontinents(color = 'gray')
map2.drawmapboundary()
map2.drawmeridians(np.arange(0, 360, 30))
map2.drawparallels(np.arange(-90, 90, 30))

x,y = map2(eq_data['longitude'].values, eq_data['latitude'].values)

map2.plot(x,y, marker='o', color='red', markersize=6, linestyle='')

使用底图和 Pandas 的 AssertionError

AssertionError using Basemap and Pandas

python

pandas