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.

Added 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.