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_func : callable
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. fromsys : class
The coordinate frame class to start from.
 tosys : class
The coordinate frame class to transform into.
 priority : number
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:  fromcoord : fromsys object
An object of class matching
fromsys
that is to be transformed. toframe : object
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:  tocoord : tosys object
The new coordinate after the transform has been applied.