Importing & Exporting

NCToolkit can work with data available on local file systems, at urls, and over thredds and OPeNDAP.

Opening single files & ensembles

To import a single netCDF file as a dataset:

python

import nctoolkit as nc
ds = nc.open_data(infile)

open_data can also import multiple files, either as a list, or using a wildcard over a folder:

python

ds = nc.open_data(file_list)
ds = nc.open_data("data/*.nc")

To work with a file available at a url or ftp address, use open_url. This downloads the file to a temporary folder first, then opens it:

python

ds = nc.open_url("www.foo.nc")

To work with data available over a thredds server or OPeNDAP, use open_thredds. The url must end with .nc:

python

ds = nc.open_thredds("www.foo.nc")

The method to_nc lets you export a dataset to a netCDF file. Use zip first if you want a compressed file:

python

ds = nc.open_data(infile)
ds.tmean()
ds.zip()
ds.to_nc(outfile)

to_dataframe exports to a pandas dataframe, and to_xarray/from_xarray move a dataset to and from xarray:

python

ds = nc.open_data(infile)
ds.tmean()
df = ds.to_dataframe()

xr_ds = ds.to_xarray()
ds2 = nc.from_xarray(xr_ds)

Pass subset arguments straight to to_nc, to_xarray or to_dataframe to export only part of a dataset:

python

ds.to_xarray(year=2000)
ds.to_xarray(lon=[0, 90], lat=[0, 90])