RadialRepresentation¶

class
astropy.coordinates.
RadialRepresentation
(distance, differentials=None, copy=True)[source]¶ Bases:
astropy.coordinates.BaseRepresentation
Representation of the distance of points from the origin.
Note that this is mostly intended as an internal helper representation. It can do little else but being used as a scale in multiplication.
Parameters:  distance :
Quantity
The distance of the point(s) from the origin.
 differentials : dict,
BaseDifferential
, optional Any differential classes that should be associated with this representation. The input must either be a single
BaseDifferential
instance (see_compatible_differentials
for valid types), or a dictionary of of differential instances with keys set to a string representation of the SI unit with which the differential (derivative) is taken. For example, for a velocity differential on a positional representation, the key would be's'
for seconds, indicating that the derivative is a time derivative. copy : bool, optional
If
True
(default), arrays will be copied rather than referenced.
Attributes Summary
attr_classes
distance
The distance from the origin to the point(s). Methods Summary
from_cartesian
(cart)Converts 3D rectangular cartesian coordinates to radial coordinate. norm
()Vector norm. scale_factors
()Scale factors for each component’s direction. to_cartesian
()Cannot convert radial representation to cartesian. unit_vectors
()Cartesian unit vectors are undefined for radial representation. Attributes Documentation

attr_classes
= {'distance': <class 'astropy.units.quantity.Quantity'>}¶

distance
¶ The distance from the origin to the point(s).
Methods Documentation

classmethod
from_cartesian
(cart)[source]¶ Converts 3D rectangular cartesian coordinates to radial coordinate.

norm
()[source]¶ Vector norm.
Just the distance itself.
Returns:  norm :
Quantity
Dimensionless ones, with the same shape as the representation.
 norm :

scale_factors
()[source]¶ Scale factors for each component’s direction.
Given unit vectors \(\hat{e}_c\) and scale factors \(f_c\), a change in one component of \(\delta c\) corresponds to a change in representation of \(\delta c \times f_c \times \hat{e}_c\).
Returns:  scale_factors : dict of
Quantity
The keys are the component names.
 scale_factors : dict of
 distance :