Reading ESA CCI SM images

To read the ESA CCI image data we recommend to use python tools such as xarray or netCDF4.

However, there are also reader classes provided in this package. These are mainly used by the image-to-timeseries conversion tool.

Reading of the ESA CCI SM raw netcdf files can be done in two ways.

Reading by file name

import os
from datetime import datetime
from esa_cci_sm.interface import CCI_SM_025Img
import numpy.testing as nptest

# read several parameters
parameter = ['sm', 'sm_uncertainty']
# the class is initialized with the exact filename.
image_path = os.path.join(os.path.dirname(__file__), 'tests', 'esa_cci_sm-test-data',
                          'esa_cci_sm_dailyImages', 'v04.2', 'combined', '2016')
image_file = 'ESACCI-SOILMOISTURE-L3S-SSMV-COMBINED-20160607000000-fv04.2.nc'
img = CCI_SM_025Img(os.path.join(image_path, image_file), parameter=parameter)

# reading returns an image object which contains a data dictionary
# with one array per parameter. The returned data is a global 0.25 degree
# image/array.
image = img.read()

Reading by date

All the ESA CCI SM data in a directory structure can be accessed by date. The filename is automatically built from the given date.

from esa_cci_sm.interface import CCI_SM_025Ds

parameter = 'sm'
img = CCI_SM_025Ds(data_path=os.path.join(os.path.dirname(__file__),
                                                'tests', 'esa_cci_sm-test-data', 'esa_cci_sm_dailyImages',
                                                'v04.2', 'combined'),
                          parameter=parameter)

image = img.read(datetime(2016, 6, 7, 0))

For reading all image between two dates the esa_cci_sm.interface.CCI_SM_025Ds.iter_images() iterator can be used.