interpolate.py

import xarray
import scipy
import numpy as np

def interpolate_points(
        grid_lons, grid_lats,
        lons, lats, values,
        method='cubic'):
    """
    Interpolate point data onto the DataArray
    
    grid_lons: Longitude axis of the grid
    grid_lats: Latitude axis of the grid
    lons: Longitude of each point
    lats: Latitude of each point
    values: Value of each point
    method: scipy.interpolate.griddata method to use

    returns: xarray.DataArray holding the gridded data
    """
    array = scipy.interpolate.griddata(
            (lons, lats), values,
            (grid_lons, grid_lats),
            method=method)
    darray = xarray.DataArray(array,
            coords = [lons, lats],
            dims = ['lon', 'lat'])
    return darray

# Read lons, lats, values somehow
lons, lats, values = read_data(input_file)

# Interpolate the values to a grid
da = interpolate_points(
        grid_lons = np.linspace(0, 360), 
        grid_lats = np.linspace(-90,90),
        lons=lons, lats=lats, values=values)

# Add metadata
da.attrs['units'] = 'degreesC'

# Put into a dataset and write to a file
ds = xarray.DataSet({'temperature': da})
ds.to_netcdf('temperature.nc')