Importing and exporting data¶
nctoolkit can work with data available on local file systems, urls and over thredds and OPeNDAP.
Opening single files and ensembles¶
If you want to import a single netCDF file as a dataset, do the following:
import nctoolkit as nc ds = nc.open_data(infile)
The open_data function can also import multiple files. This can be done in two ways. If we have a list of files we can do the following:
import nctoolkit as nc ds = nc.open_data(file_list)
Alternatively, open_data is capable of handling wildcards. So if we have a folder called data, we can import all files in it as follows:
import nctoolkit as nc ds = nc.open_data("data/*.nc")
Opening files from urls/ftp¶
If we want to work with a file that is available at a url or ftp, we can use the open_url function. This will start by downloading the file to a temporary folder, so that it can be analysed.
import nctoolkit as nc ds = nc.open_url(www.foo.nc)
Opening data available over thredds servers or OPeNDAP¶
If you want to work with data that is available over a thredds server or OPeNDAP, you can use the open_thredds method. This will require that the url ends with “.nc”.
import nctoolkit as nc ds = nc.open_thredds(www.foo.nc)
nctoolkit has a number of built in methods for exporting data to netCDF, pandas dataframes and xarray datasets.
Save as a netCDF¶
to_nc lets users export a dataset to a netCDF file. If
you want this to be a zipped netCDF file use the
zip method before
to_nc. An example of usage is as follows:
ds = nc.open_data(infile) ds.tmean() ds.zip() ds.to_nc(outfile)
Convert to pandas dataframe¶
to_dataframe lets users export a dataset to a pandas
ds = nc.open_data(infile) ds.tmean() df = ds.to_dataframe()
Interacting with xarray datasets¶
If you want to move between nctoolkit and xarray dataset, you can use
to_xarray lets users export a dataset to an xarray
dataset. An example of usage is as follows:
ds = nc.open_data(infile) ds.tmean() xr_ds = ds.to_xarray()
If you want to convert an xarray dataset to an nctoolkit dataset, you can just the
from_xarray function, as follows: