Question

I'm trying to convert a netCDF file to either a CSV or text file using Python. I have read this post but I am still missing a step (I'm new to Python). It's a dataset including latitude, longitude, time and precipitation data.

This is my code so far:

import netCDF4
import pandas as pd

precip_nc_file = 'file_path'
nc = netCDF4.Dataset(precip_nc_file, mode='r')

nc.variables.keys()

lat = nc.variables['lat'][:]
lon = nc.variables['lon'][:]
time_var = nc.variables['time']
dtime = netCDF4.num2date(time_var[:],time_var.units)
precip = nc.variables['precip'][:]

I am not sure how to proceed from here, though I understand it's a matter of creating a dataframe with pandas.

Answer 1

我认为pandas.Series应该可以让你创建一个包含时间，纬度，经度，沉降的CSV。

import netCDF4
import pandas as pd

precip_nc_file = 'file_path'
nc = netCDF4.Dataset(precip_nc_file, mode='r')

nc.variables.keys()

lat = nc.variables['lat'][:]
lon = nc.variables['lon'][:]
time_var = nc.variables['time']
dtime = netCDF4.num2date(time_var[:],time_var.units)
precip = nc.variables['precip'][:]

# a pandas.Series designed for time series of a 2D lat,lon grid
precip_ts = pd.Series(precip, index=dtime) 

precip_ts.to_csv('precip.csv',index=True, header=True)

Answer 2

根据您的要求，您可以使用Numpy的savetxt方法：

import numpy as np

np.savetxt('lat.csv', lat, delimiter=',')
np.savetxt('lon.csv', lon, delimiter=',')
np.savetxt('precip.csv', precip, delimiter=',')

然而，这将输出没有任何标题或索引列的数据。

如果确实需要这些功能，可以构建一个DataFrame并将其保存为CSV，如下所示：

df_lat = pd.DataFrame(data=lat, index=dtime)
df_lat.to_csv('lat.csv')

# and the same for `lon` and `precip`.

注意：在这里，我假设日期/时间索引沿着数据的第一维运行。

Answer 3

import xarray as xr

nc = xr.open_dataset('file_path')
nc.precip.to_dataframe().to_csv('precip.csv')

Convert NetCDF file to CSV or text using Python

3 个答案: