BaseDifferential¶

class
astropy.coordinates.
BaseDifferential
(*args, **kwargs)[source]¶ Bases:
astropy.coordinates.BaseRepresentationOrDifferential
A base class representing differentials of representations.
These represent differences or derivatives along each component. E.g., for physics spherical coordinates, these would be \(\delta r, \delta \theta, \delta \phi\).
Parameters: Notes
All differential representation classes should subclass this base class, and define an
base_representation
attribute with the class of the regularBaseRepresentation
for which differential coordinates are provided. This will set up a defaultattr_classes
instance with names equal to the base component names prefixed byd_
, and all classes set toQuantity
, plus properties to access those, and a default__init__
for initialization.Methods Summary
from_cartesian
(other, base)Convert the differential from 3D rectangular cartesian coordinates to the desired class. from_representation
(representation, base)Create a new instance of this representation from another one. norm
(self[, base])Vector norm. represent_as
(self, other_class, base)Convert coordinates to another representation. to_cartesian
(self, base)Convert the differential to 3D rectangular cartesian coordinates. Methods Documentation

classmethod
from_cartesian
(other, base)[source]¶ Convert the differential from 3D rectangular cartesian coordinates to the desired class.
Parameters:  other :
The object to convert into this differential.
 base : instance of
self.base_representation
The points for which the differentials are to be converted: each of the components is multiplied by its unit vectors and scale factors.
Returns:  A new differential object that is this class’ type.

classmethod
from_representation
(representation, base)[source]¶ Create a new instance of this representation from another one.
Parameters:  representation :
BaseRepresentation
instance The presentation that should be converted to this class.
 base : instance of
cls.base_representation
The base relative to which the differentials will be defined. If the representation is a differential itself, the base will be converted to its
base_representation
to help convert it.
 representation :

norm
(self, base=None)[source]¶ Vector norm.
The norm is the standard Frobenius norm, i.e., the square root of the sum of the squares of all components with nonangular units.
Parameters:  base : instance of
self.base_representation
Base relative to which the differentials are defined. This is required to calculate the physical size of the differential for all but cartesian differentials.
Returns:  norm :
astropy.units.Quantity
Vector norm, with the same shape as the representation.
 base : instance of

represent_as
(self, other_class, base)[source]¶ Convert coordinates to another representation.
If the instance is of the requested class, it is returned unmodified. By default, conversion is done via cartesian coordinates.
Parameters:  other_class :
BaseRepresentation
subclass The type of representation to turn the coordinates into.
 base : instance of
self.base_representation
, optional Base relative to which the differentials are defined. If the other class is a differential representation, the base will be converted to its
base_representation
.
 other_class :

to_cartesian
(self, base)[source]¶ Convert the differential to 3D rectangular cartesian coordinates.
Parameters:  base : instance of
self.base_representation
The points for which the differentials are to be converted: each of the components is multiplied by its unit vectors and scale factors.
Returns:  This object as a
CartesianDifferential
 base : instance of

classmethod