# CartesianDifferential#

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

Bases: BaseDifferential

Differentials in of points in 3D cartesian coordinates.

Parameters:
d_x, d_y, d_z

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 str

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

xyz_axisint, 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_axisint, 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)[source]#

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)[source]#

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

Parameters:
xyz_axisint, 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)[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=None, transformed_base=None)[source]#

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) array_like

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

base, transformed_baseCartesianRepresentation or None, optional

Not used in the Cartesian transformation.