cf.Datum

---

class cf.Datum(parameters=None, source=None, copy=True)

Bases: cfdm.datum.Datum

A datum component of a coordinate reference construct of the CF data model.

A datum is a complete or partial definition of the zeroes of the dimension and auxiliary coordinate constructs which define a coordinate system.

The datum may contain the definition of a geophysical surface which corresponds to the zero of a vertical coordinate construct, and this may be required for both horizontal and vertical coordinate systems.

Elements of the datum not specified may be implied by the properties of the dimension and auxiliary coordinate constructs referenced by the cf.CoordinateReference instance that contains the datum.

New in version 3.0.0.

Initialisation

Parameters

parameters: dict, optional

Set parameters. The dictionary keys are parameter names, with corresponding values.

Parameters may also be set after initialisation with the set_parameters and set_parameter methods.

Parameter example:

parameters={'earth_radius': 6371007.}

source: optional

Convert source, which can be any type of object, to a Datum instance.

All other parameters, apart from copy, are ignored and their values are instead inferred from source by assuming that it has the Datum API. Any parameters that can not be retrieved from source in this way are assumed to have their default value.

Note that if x is also a Datum instance then cf.Datum(source=x) is equivalent to x.copy().

copy: bool, optional

If True (the default) then deep copy the input parameters prior to initialisation. By default the parameters are not deep copied.

Parameters

Methods

clear_parameters	Remove all parameters.
del_parameter	Delete a parameter.
get_parameter	Get a parameter value.
has_parameter	Whether a parameter has been set.
parameters	Return all parameters.
set_parameter	Set a parameter-valued term.
set_parameters	Set parameters.

NetCDF

Methods

nc_del_variable	Remove the netCDF variable name.
nc_get_variable	Return the netCDF variable name.
nc_has_variable	Whether the netCDF variable name has been set.
nc_set_variable	Set the netCDF variable name.

Miscellaneous

Methods

copy	Return a deep copy.
get_original_filenames	The names of files containing the original data and metadata.
equals	Whether two instances are the same.

Groups

Methods

nc_variable_groups	Return the netCDF variable group hierarchy.
nc_set_variable_groups	Set the netCDF variable group hierarchy.
nc_clear_variable_groups	Remove the netCDF variable group hierarchy.

Special

Methods

__bool__	Called by the bool built-in function.
__deepcopy__	Called by the copy.deepcopy function.
cf.Datum.__nonzero__
__repr__	Called by the repr built-in function.
__str__	Called by the str built-in function.