AffineTransform¶

class
astropy.coordinates.
AffineTransform
(transform_func, fromsys, tosys, priority=1, register_graph=None)[source]¶ Bases:
astropy.coordinates.BaseAffineTransform
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 onfromcoord
in a Cartesian representation, and aCartesianRepresentation
with (optionally) an attached velocityCartesianDifferential
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.
 prioritynumber
The priority if this transform when finding the shortest coordinate transform path  large numbers are lower priorities.
 register_graph
TransformGraph
orNone
A graph to register this transformation with on creation, or
None
to leave it unregistered.
 Raises
 TypeError
If
transform_func
is not callable
Methods Summary
__call__
(self, fromcoord, toframe)Does the actual coordinate transformation from the
fromsys
class to thetosys
class.Methods Documentation

__call__
(self, fromcoord, toframe)[source]¶ Does the actual coordinate transformation from the
fromsys
class to thetosys
class. Parameters
 fromcoordfromsys object
An object of class matching
fromsys
that is to be transformed. toframeobject
An object that has the attributes necessary to fully specify the frame. That is, it must have attributes with names that match the keys of the dictionary that
tosys.get_frame_attr_names()
returns. Typically this is of classtosys
, but it might be some other class as long as it has the appropriate attributes.
 Returns
 tocoordtosys object
The new coordinate after the transform has been applied.