AffineTransform#

class astropy.coordinates.AffineTransform(transform_func, fromsys, tosys, priority=1, register_graph=None)[source]#

A coordinate transformation specified as a function that yields a 3 x 3 cartesian transformation matrix and a tuple of displacement vectors.

See Galactocentric for an example.

Parameters:

transform_funccallable(): A callable that has the signature transform_func(fromcoord, toframe) and returns: a (3, 3) matrix that operates on fromcoord in a Cartesian representation, and a CartesianRepresentation with (optionally) an attached velocity CartesianDifferential to represent a translation and offset in velocity to apply after the matrix operation.
fromsysclass: The coordinate frame class to start from.
tosysclass: The coordinate frame class to transform into.
priorityfloat or int: The priority if this transform when finding the shortest coordinate transform path - large numbers are lower priorities.
register_graphTransformGraph or None: A graph to register this transformation with on creation, or None to leave it unregistered.

Raises: