CoordinateTransform¶

class
astropy.coordinates.
CoordinateTransform
(fromsys, tosys, priority=1, register_graph=None)[source] [edit on github]¶ 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 : 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.
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

__call__
(fromcoord, toframe)[source] [edit on github]¶ 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.

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

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