cfdm.Datum

---

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

Bases: cfdm.mixin.parameters.Parameters, cfdm.mixin.netcdf.NetCDFVariable, cfdm.mixin.files.Files, cfdm.core.datum.Datum

A datum component of a CF data model coordinate reference.

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 CoordinateReference instance that contains the datum.

NetCDF interface

The netCDF variable name may be accessed with the nc_set_variable, nc_get_variable, nc_del_variable, and nc_has_variable methods.

The netCDF variable group structure may be accessed with the nc_set_variable, nc_get_variable, nc_variable_groups, nc_clear_variable_groups, and nc_set_variable_groups methods.

New in version (cfdm): 1.7.0

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 cfdm.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.

Parameter terms

Methods

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

Miscellaneous

Methods

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

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.

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.
__repr__	Called by the repr built-in function.
__str__	Called by the str built-in function.

Docstring substitutions

Methods

_docstring_special_substitutions	Return the special docstring substitutions.
_docstring_substitutions	Returns the substitutions that apply to methods of the class.
_docstring_package_depth	Returns the class {{package}} substitutions package depth.
_docstring_method_exclusions	Returns method names excluded in the class substitutions.