With this method you can create a longitude axis to use with new CFVariable instances.
makeLongitudeAxis(name, values, bounds = NULL, attributes = NULL)A CFAxisLongitude instance.
Name of the axis.
The coordinate values.
The bounds of the coordinate values, or NULL if not
available.
data.frame with the attributes of the axis to create.
Attributes "standard_name", "units", "actual_range" and "axis" will be set
or updated.