CartesianDifferential

class astropy.coordinates.CartesianDifferential(d_x, d_y=None, d_z=None, unit=None, xyz_axis=None, copy=True)

Bases: BaseDifferential

Differentials in of points in 3D cartesian coordinates.

Parameters:

d_x, d_y, d_zQuantity or array

The x, y, and z coordinates of the differentials. If d_x, d_y, and d_z have different shapes, they should be broadcastable. If not quantities, unit should be set. If only d_x is given, it is assumed that it contains an array with the 3 coordinates stored along xyz_axis.

unitUnit or python:str

If given, the differentials will be converted to this unit (or taken to be in this unit if not given.

xyz_axispython:int, optional

The axis along which the coordinates are stored when a single array is provided instead of distinct d_x, d_y, and d_z (default: 0).

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_x	Component 'd_x' of the Differential.
d_xyz	Return a vector array of the x, y, and z coordinates.
d_y	Component 'd_y' of the Differential.
d_z	Component 'd_z' of the Differential.

Methods Summary

from_cartesian(other[, base])	Convert the differential from 3D rectangular cartesian coordinates to the desired class.
get_d_xyz([xyz_axis])	Return a vector array of the x, y, and z coordinates.
to_cartesian([base])	Convert the differential to 3D rectangular cartesian coordinates.
transform(matrix[, base, transformed_base])	Transform differentials using a 3x3 matrix in a Cartesian basis.

Attributes Documentation

attr_classes = {'d_x': <class 'astropy.units.quantity.Quantity'>, 'd_y': <class 'astropy.units.quantity.Quantity'>, 'd_z': <class 'astropy.units.quantity.Quantity'>}

d_x

Component ‘d_x’ of the Differential.

d_xyz

Return a vector array of the x, y, and z coordinates.

Parameters:

xyz_axispython:int, optional

The axis in the final array along which the x, y, z components should be stored (default: 0).

Returns:

d_xyzQuantity

With dimension 3 along xyz_axis. Note that, if possible, this will be a view.

d_y

Component ‘d_y’ of the Differential.

d_z

Component ‘d_z’ of the Differential.

Methods Documentation

classmethod from_cartesian(other, base=None)

Convert the differential from 3D rectangular cartesian coordinates to the desired class.

Parameters:

other

The object to convert into this differential.

baseBaseRepresentation

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.

get_d_xyz(xyz_axis=0)

Return a vector array of the x, y, and z coordinates.

Parameters:

xyz_axispython:int, optional

The axis in the final array along which the x, y, z components should be stored (default: 0).

Returns:

d_xyzQuantity

With dimension 3 along xyz_axis. Note that, if possible, this will be a view.

to_cartesian(base=None)

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=None, transformed_base=None)

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

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

Parameters:

matrix(3,3) numpy:array_like

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

base, transformed_baseCartesianRepresentation or python:None, optional

Not used in the Cartesian transformation.