# UnitSphericalDifferential¶

class astropy.coordinates.UnitSphericalDifferential(d_lon, d_lat=None, copy=True)[source]

Differential(s) of points on a unit sphere.

Parameters:
d_lon, d_lat`Quantity`

The longitude and latitude of the differentials.

copybool, optional

If `True` (default), arrays will be copied. If `False`, arrays will be references, though possibly broadcast to ensure matching shapes.

Attributes Summary

 `attr_classes` `d_lat` Component 'd_lat' of the Differential. `d_lon` Component 'd_lon' of the Differential.

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. `represent_as`(other_class[, base]) Convert coordinates to another representation. `to_cartesian`(base) Convert the differential to 3D rectangular cartesian coordinates. `transform`(matrix, base, transformed_base) Transform differential using a 3x3 matrix in a Cartesian basis.

Attributes Documentation

attr_classes = {'d_lat': <class 'astropy.units.quantity.Quantity'>, 'd_lon': <class 'astropy.units.quantity.Quantity'>}
d_lat

Component ‘d_lat’ of the Differential.

d_lon

Component ‘d_lon’ of the Differential.

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`BaseRepresentation`

The points for which the differentials are to be converted: each of the components is multiplied by its unit vectors and scale factors. Will be converted to `cls.base_representation` if needed.

Returns:
`BaseDifferential` subclass instance

A new differential object that is this class’ type.

classmethod from_representation(representation, base=None)[source]

Create a new instance of this representation from another one.

Parameters:
representation`BaseRepresentation` instance

The presentation that should be converted to this class.

baseinstance 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.

represent_as(other_class, base=None)[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.

baseinstance of `self.base_representation`

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`.

to_cartesian(base)[source]

Convert the differential to 3D rectangular cartesian coordinates.

Parameters:
baseinstance 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:
`CartesianDifferential`

This object, converted.

transform(matrix, base, transformed_base)[source]

Transform differential using a 3x3 matrix in a Cartesian basis.

This returns a new differential and does not modify the original one.

Parameters:
matrix(3,3) array_like

A 3x3 (or stack thereof) matrix, such as a rotation matrix.

baseinstance of `cls.base_representation`

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`.

transformed_baseinstance of `cls.base_representation`

Base relative to which the transformed differentials are defined. If the other class is a differential representation, the base will be converted to its `base_representation`.