# CompositeTransform¶

class astropy.coordinates.CompositeTransform(transforms, fromsys, tosys, priority=1, register_graph=None, collapse_static_mats=True)[source]

A transformation constructed by combining together a series of single-step transformations.

Note that the intermediate frame objects are constructed using any frame attributes in toframe or fromframe that overlap with the intermediate frame (toframe favored over fromframe if there’s a conflict). Any frame attributes that are not present use the defaults.

Parameters: transforms : sequence of CoordinateTransform objects The sequence of transformations to apply. 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 : A graph to register this transformation with on creation, or None to leave it unregistered. collapse_static_mats : bool If True, consecutive StaticMatrixTransform will be collapsed into a single transformation to speed up the calculation.

Methods Summary

 __call__(self, fromcoord, toframe) Does the actual coordinate transformation from the fromsys class to the tosys class.

Methods Documentation

__call__(self, fromcoord, toframe)[source]

Does the actual coordinate transformation from the fromsys class to the tosys 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 class tosys, but it might be some other class as long as it has the appropriate attributes. tocoord : tosys object The new coordinate after the transform has been applied.