CoordinateTransform¶

class
astropy.coordinates.
CoordinateTransform
(fromsys, tosys, priority=1, register_graph=None)[source]¶ Bases:
object
An object that transforms a coordinate from one system to another. Subclasses must implement
__call__
with the provided signature. They should also call this superclass’s__init__
in their__init__
. Parameters
 fromsys
BaseCoordinateFrame
subclass The coordinate frame class to start from.
 tosys
BaseCoordinateFrame
subclass The coordinate frame class to transform into.
 priority
float
orint
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.
 fromsys
Methods Summary
__call__
(fromcoord, toframe)Does the actual coordinate transformation from the
fromsys
class to thetosys
class.register
(graph)Add this transformation to the requested Transformation graph, replacing anything already connecting these two coordinates.
unregister
(graph)Remove this transformation from the requested transformation graph.
Methods Documentation

abstract
__call__
(fromcoord, toframe)[source]¶ Does the actual coordinate transformation from the
fromsys
class to thetosys
class. Parameters
 fromcoord
BaseCoordinateFrame
subclass instance 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.
 fromcoord
 Returns
 tocoord
BaseCoordinateFrame
subclass instance The new coordinate after the transform has been applied.
 tocoord

register
(graph)[source]¶ Add this transformation to the requested Transformation graph, replacing anything already connecting these two coordinates.
 Parameters
 graph
TransformGraph
object
The graph to register this transformation with.
 graph

unregister
(graph)[source]¶ Remove this transformation from the requested transformation graph.
 Parameters
 graph
a
TransformGraph
object
The graph to unregister this transformation from.
 graph
 Raises
ValueError
If this is not currently in the transform graph.