CartesianRepresentation

class astropy.coordinates.CartesianRepresentation(x, y=None, z=None, copy=True)

Bases: astropy.coordinates.BaseRepresentation

Representation of points in 3D cartesian coordinates.

Parameters:

x, y, z : Quantity

The x, y, and z coordinates of the point(s). If x, y, and z have different shapes, they should be broadcastable.

copy : bool, optional

If True arrays will be copied rather than referenced.

Attributes Summary

attr_classes
x	The x component of the point(s).
xyz
y	The y component of the point(s).
z	The z component of the point(s).

Methods Summary

from_cartesian(other)
to_cartesian()
transform(matrix)	Transform the cartesian coordinates using a 3x3 matrix.

Attributes Documentation

attr_classes = OrderedDict([(u'x', <class 'astropy.units.quantity.Quantity'>), (u'y', <class 'astropy.units.quantity.Quantity'>), (u'z', <class 'astropy.units.quantity.Quantity'>)])

x

The x component of the point(s).

xyz

y

The y component of the point(s).

z

The z component of the point(s).

Methods Documentation

classmethod from_cartesian(other)

to_cartesian()

transform(matrix)

Transform the cartesian coordinates using a 3x3 matrix.

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

Parameters:

matrix : ndarray

A 3x3 transformation matrix, such as a rotation matrix.

Examples

We can start off by creating a cartesian representation object:

>>> from astropy import units as u
>>> from astropy.coordinates import CartesianRepresentation
>>> rep = CartesianRepresentation([1, 2] * u.pc,
...                               [2, 3] * u.pc,
...                               [3, 4] * u.pc)

We now create a rotation matrix around the z axis:

>>> from astropy.coordinates.angles import rotation_matrix
>>> rotation = rotation_matrix(30 * u.deg, axis='z')

Finally, we can apply this transformation:

>>> rep_new = rep.transform(rotation)
>>> rep_new.xyz  
<Quantity [[ 1.8660254 , 3.23205081],
           [ 1.23205081, 1.59807621],
           [ 3.        , 4.        ]] pc>