Question

我尝试将我的数据从一个大的netCDF文件转换为一个特殊点的ascii格式文件（68,21）。当我尝试运行以下内容时：

from pylab import *
from netCDF4 import Dataset
import pandas as pd

nc = Dataset("/home/python/PBLH_Exp_08_Jul_2006.nc")

PBLH = nc.variables['PBLH'][:,:,:]
Times = nc.variables['Times'][:,:]

d={}
d['Times'] = Times[:,0]
d['PBLH'] = PBLH[:,:,1]

df=pd.DataFrame(d)
df.to_csv('Produkt/PBLH_Exp_08_Jul_2006.csv')

我收到了错误消息：

Traceback (most recent call last):
  File "/home/python/wrf_map.py", line 62, in <module>
    df=pd.DataFrame(d)
  File "/usr/local/lib/python2.7/dist-packages/pandas/core/frame.py", line 226, in __init__
    mgr = self._init_dict(data, index, columns, dtype=dtype)
  File "/usr/local/lib/python2.7/dist-packages/pandas/core/frame.py", line 363, in _init_dict
dtype=dtype)
  File "/usr/local/lib/python2.7/dist-packages/pandas/core/frame.py", line 5163, in _arrays_to_mgr
    arrays = _homogenize(arrays, index, dtype)
  File "/usr/local/lib/python2.7/dist-packages/pandas/core/frame.py", line 5477, in _homogenize
raise_cast_failure=False)
  File "/usr/local/lib/python2.7/dist-packages/pandas/core/series.py", line 2885, in _sanitize_array
    raise Exception('Data must be 1-dimensional')
Exception: Data must be 1-dimensional

我该怎么做才能解决这个问题？如何为网格点提取数据？顺便说一句，这是我的netCDF文件的标题的一部分：

<xarray.Dataset>
Dimensions:      (Time: 744, south_north: 140, west_east: 140)
Coordinates:

  * Time         (Time) int64 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 ...
  * south_north  (south_north) int64 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 ...
  * west_east    (west_east) int64 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 ...
Data variables:
    Times        (Time) |S19 '2006-07-01_01:00:00' '2006-07-01_02:00:00' ...
    PBLH         (Time, south_north, west_east) float32 59.9834 59.8574 ...

感谢您的帮助!!

Answer 1

我解决了我的一部分问题。我使用xarray来获取我想要的数据（对于具有网格点21,68的位置）：

import numpy as np
import xray as xr
from pylab import *

data = xr.open_dataset("/home/python/PBLH_Exp_08_jul_2006.nc")
d = xr.DataArray(data.variables['PBLH'])
print(d[:,21,68])

但我仍然无法将数据保存在ASCII文件中......

编辑：知道了！为了保存我的数据，我使用了import csv。然后我写道：

df = d[:,21,68]
with open ('/home/python/output.txt','w') as fout:
    writer = csv.writer(fout)
    writer.writerows(df)

它看起来不那么漂亮，但我可以处理它！所以这应该适用于所有有类似问题的人！：）

如何在ASCII格式文件中转换netCDF4文件以获取Python中的特殊网格点？

1 个答案: