QuantityAttribute¶

class astropy.coordinates.QuantityAttribute(default=None, secondary_attribute='', unit=None, shape=None)[source] [edit on github]¶

A frame attribute that is a quantity with specified units and shape (optionally).

Parameters:

default : object: Default value for the attribute if not provided
secondary_attribute : str: Name of a secondary instance attribute which supplies the value if default is None and no value was supplied during initialization.
unit : unit object or None: Name of a unit that the input will be converted into. If None, no unit-checking or conversion is performed
shape : tuple or None: If given, specifies the shape the attribute must be

Methods Summary

convert_input(value) Checks that the input is a Quantity with the necessary units (or the special value 0).

Methods Documentation

Checks that the input is a Quantity with the necessary units (or the special value 0).

Parameters:	value : object Input value to be converted.
Returns:	out, converted : correctly-typed object, boolean Tuple consisting of the correctly-typed object and a boolean which indicates if conversion was actually performed.
Raises:	ValueError If the input is not valid for this attribute.