QuantityAttribute

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

Bases: astropy.coordinates.Attribute

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

Methods Documentation

convert_input(self, value)[source]

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.