底图/项目的Pandas错误，用于地图绘制

问题描述

我在下面的Python代码中运行了该代码，该代码示例是用于数据分析的Python 一书中的绘制地图:可视化海地地震危机数据".第242-246页

该代码应该会创建海地的情节地图，但出现以下错误:

Traceback (most recent call last):
  File "Haiti.py", line 74, in <module>
    x, y = m(cat_data.LONGITUDE, cat_data.LATITUDE)
  File "/usr/local/lib/python2.7/site-packages/mpl_toolkits/basemap/__init__.py", line 1148, in __call__
    xout,yout = self.projtran(x,y,inverse=inverse)
  File "/usr/local/lib/python2.7/site-packages/mpl_toolkits/basemap/proj.py", line 286, in __call__
    outx,outy = self._proj4(x, y, inverse=inverse)
  File "/usr/local/lib/python2.7/site-packages/mpl_toolkits/basemap/pyproj.py", line 388, in __call__
    _proj.Proj._fwd(self, inx, iny, radians=radians, errcheck=errcheck)
  File "_proj.pyx", line 122, in _proj.Proj._fwd (src/_proj.c:1571)
RuntimeError

我检查了我计算机上是否已正确安装 mpl_toolkits.basemap 和 proj 模块.按照指示从源安装安装底图，然后由Homebrew安装了proj，它们看起来还不错对我来说.

如果已安装底图和proj，此代码是否成功运行?如果不是，您是否认为这是模块安装问题，代码本身还是其他问题?

可以从 Haiti.csv 文件nofollow> https://github.com/pydata/pydata-book/raw/master/ch08/Haiti.csv

import pandas as pd
import numpy as np
from pandas import DataFrame

data = pd.read_csv('Haiti.csv')

data = data[(data.LATITUDE > 18) & (data.LATITUDE < 20) &
        (data.LONGITUDE > -75) & (data.LONGITUDE < -70)
        & data.CATEGORY.notnull()]

def to_cat_list(catstr):
    stripped = (x.strip() for x in catstr.split(','))
    return [x for x in stripped if x]

def get_all_categories(cat_series):
    cat_sets = (set(to_cat_list(x)) for x in cat_series) 
    return sorted(set.union(*cat_sets))

def get_english(cat):
    code, names = cat.split('.') 
    if '|' in names:
        names = names.split(' | ')[1] 
    return code, names.strip()

all_cats = get_all_categories(data.CATEGORY)
english_mapping = dict(get_english(x) for x in all_cats)

def get_code(seq):
    return [x.split('.')[0] for x in seq if x]

all_codes = get_code(all_cats)
code_index = pd.Index(np.unique(all_codes))
dummy_frame = DataFrame(np.zeros((len(data), len(code_index))),
                        index=data.index, columns=code_index)

for row, cat in zip(data.index, data.CATEGORY): 
    codes = get_code(to_cat_list(cat)) 
    dummy_frame.ix[row, codes] = 1

data = data.join(dummy_frame.add_prefix('category_'))

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

def basic_haiti_map(ax=None, lllat=17.25, urlat=20.25, lllon=-75, urlon=-71):
    # create polar stereographic Basemap instance. 
    m = Basemap(ax=ax, projection='stere', 
                lon_0=(urlon + lllon) / 2, 
                lat_0=(urlat + lllat) / 2,
                llcrnrlat=lllat, urcrnrlat=urlat, 
                llcrnrlon=lllon, urcrnrlon=urlon, 
                resolution='f')
    # draw coastlines, state and country boundaries, edge of map. m.drawcoastlines()
    m.drawstates()
    m.drawcountries()
    return m

fig, axes = plt.subplots(nrows=2, ncols=2, figsize=(12, 10)) 
fig.subplots_adjust(hspace=0.05, wspace=0.05)

to_plot = ['2a', '1', '3c', '7a']

lllat=17.25; urlat=20.25; lllon=-75; urlon=-71

for code, ax in zip(to_plot, axes.flat):
    m = basic_haiti_map(ax, lllat=lllat, urlat=urlat,
                        lllon=lllon, urlon=urlon) 

    cat_data = data[data['category_%s' % code] == 1]

    # compute map proj coordinates.
    print cat_data.LONGITUDE, cat_data.LATITUDE
    x, y = m(cat_data.LONGITUDE, cat_data.LATITUDE)

    m.plot(x, y, 'k.', alpha=0.5)
    ax.set_title('%s: %s' % (code, english_mapping[code]))

解决方案

这可以通过以下方式解决:将m(cat_data.LONGITUDE，cat_data.LATITUDE)更改为m(cat_data.LONGITUDE.values，cat_data.LATITUDE.values) Alex Messina的发现.

对我的进一步研究后，熊猫改变了自2013年12月31日发布v0.13.0以来，DataFrame的Series数据(源自NDFrame)应与.values一起传递给像basemap/proj这样的Cython函数的方法. /p>

来自 github提交日志的报价:

+.. warning::
 +
 +   In 0.13.0 since ``Series`` has internaly been refactored to no longer sub-class ``ndarray``
 +   but instead subclass ``NDFrame``, you can **not pass** a ``Series`` directly as a ``ndarray`` typed parameter
 +   to a cython function. Instead pass the actual ``ndarray`` using the ``.values`` attribute of the Series.
 +
 +   Prior to 0.13.0
 +
 +   .. code-block:: python
 +
 +        apply_integrate_f(df['a'], df['b'], df['N'])
 +
 +   Use ``.values`` to get the underlying ``ndarray``
 +
 +   .. code-block:: python
 +
 +        apply_integrate_f(df['a'].values, df['b'].values, df['N'].values)

您可以在此处找到正确的示例代码版本.

I ran the Python code below that is an example of "Plotting Maps: Visualizing Haiti Earthquake Crisis Data" on a book, Python for Data Analysis. Page 242-246

The code is supposed to create a plot map of Haiti but I got an error as below:

Traceback (most recent call last):
  File "Haiti.py", line 74, in <module>
    x, y = m(cat_data.LONGITUDE, cat_data.LATITUDE)
  File "/usr/local/lib/python2.7/site-packages/mpl_toolkits/basemap/__init__.py", line 1148, in __call__
    xout,yout = self.projtran(x,y,inverse=inverse)
  File "/usr/local/lib/python2.7/site-packages/mpl_toolkits/basemap/proj.py", line 286, in __call__
    outx,outy = self._proj4(x, y, inverse=inverse)
  File "/usr/local/lib/python2.7/site-packages/mpl_toolkits/basemap/pyproj.py", line 388, in __call__
    _proj.Proj._fwd(self, inx, iny, radians=radians, errcheck=errcheck)
  File "_proj.pyx", line 122, in _proj.Proj._fwd (src/_proj.c:1571)
RuntimeError

I checked if mpl_toolkits.basemap and proj module were installed okay on my machine. Basemap was installed from source as instructed and proj was installed by Homebrew and they looks fine to me.

If you have basemap and proj installed, does this code run successfully? If not, do you think if it's a module installation issue, the code itself, or any other?

Haiti.csv file can be downloaded from https://github.com/pydata/pydata-book/raw/master/ch08/Haiti.csv

import pandas as pd
import numpy as np
from pandas import DataFrame

data = pd.read_csv('Haiti.csv')

data = data[(data.LATITUDE > 18) & (data.LATITUDE < 20) &
        (data.LONGITUDE > -75) & (data.LONGITUDE < -70)
        & data.CATEGORY.notnull()]

def to_cat_list(catstr):
    stripped = (x.strip() for x in catstr.split(','))
    return [x for x in stripped if x]

def get_all_categories(cat_series):
    cat_sets = (set(to_cat_list(x)) for x in cat_series) 
    return sorted(set.union(*cat_sets))

def get_english(cat):
    code, names = cat.split('.') 
    if '|' in names:
        names = names.split(' | ')[1] 
    return code, names.strip()

all_cats = get_all_categories(data.CATEGORY)
english_mapping = dict(get_english(x) for x in all_cats)

def get_code(seq):
    return [x.split('.')[0] for x in seq if x]

all_codes = get_code(all_cats)
code_index = pd.Index(np.unique(all_codes))
dummy_frame = DataFrame(np.zeros((len(data), len(code_index))),
                        index=data.index, columns=code_index)

for row, cat in zip(data.index, data.CATEGORY): 
    codes = get_code(to_cat_list(cat)) 
    dummy_frame.ix[row, codes] = 1

data = data.join(dummy_frame.add_prefix('category_'))

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

def basic_haiti_map(ax=None, lllat=17.25, urlat=20.25, lllon=-75, urlon=-71):
    # create polar stereographic Basemap instance. 
    m = Basemap(ax=ax, projection='stere', 
                lon_0=(urlon + lllon) / 2, 
                lat_0=(urlat + lllat) / 2,
                llcrnrlat=lllat, urcrnrlat=urlat, 
                llcrnrlon=lllon, urcrnrlon=urlon, 
                resolution='f')
    # draw coastlines, state and country boundaries, edge of map. m.drawcoastlines()
    m.drawstates()
    m.drawcountries()
    return m

fig, axes = plt.subplots(nrows=2, ncols=2, figsize=(12, 10)) 
fig.subplots_adjust(hspace=0.05, wspace=0.05)

to_plot = ['2a', '1', '3c', '7a']

lllat=17.25; urlat=20.25; lllon=-75; urlon=-71

for code, ax in zip(to_plot, axes.flat):
    m = basic_haiti_map(ax, lllat=lllat, urlat=urlat,
                        lllon=lllon, urlon=urlon) 

    cat_data = data[data['category_%s' % code] == 1]

    # compute map proj coordinates.
    print cat_data.LONGITUDE, cat_data.LATITUDE
    x, y = m(cat_data.LONGITUDE, cat_data.LATITUDE)

    m.plot(x, y, 'k.', alpha=0.5)
    ax.set_title('%s: %s' % (code, english_mapping[code]))

解决方案

This is resolved by changing m(cat_data.LONGITUDE, cat_data.LATITUDE) to m(cat_data.LONGITUDE.values, cat_data.LATITUDE.values), thanks to Alex Messina's finding.

With a little further study of mine, pandas changed that Series data of DataFrame (derived from NDFrame) should be passed with .values to a Cython function like basemap/proj since v0.13.0 released on 31 Dec 2013 as below.

Quote from github commit log of pandas:

+.. warning::
 +
 +   In 0.13.0 since ``Series`` has internaly been refactored to no longer sub-class ``ndarray``
 +   but instead subclass ``NDFrame``, you can **not pass** a ``Series`` directly as a ``ndarray`` typed parameter
 +   to a cython function. Instead pass the actual ``ndarray`` using the ``.values`` attribute of the Series.
 +
 +   Prior to 0.13.0
 +
 +   .. code-block:: python
 +
 +        apply_integrate_f(df['a'], df['b'], df['N'])
 +
 +   Use ``.values`` to get the underlying ``ndarray``
 +
 +   .. code-block:: python
 +
 +        apply_integrate_f(df['a'].values, df['b'].values, df['N'].values)

You can find the corrected version of the example code here.

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