Typically, this might be required if the FrameSet has been used to calibrate (say) an image, and that image is re-binned. The Frame describing the image will then have undergone a coordinate transformation, and this should be communicated to the associated FrameSet using this function.
A value of AST__BASE or AST__CURRENT may be given for the
" parameter to
specify the base Frame or the current Frame respectively.
The relationship between the selected Frame and any other Frame within the FrameSet will be modified by this function, but the relationship between all other Frames in the FrameSet remains unchanged.
The number of input coordinate values accepted by the Mapping (its Nin attribute) and the number of output coordinate values generated (its Nout attribute) must be equal and must match the number of axes in the Frame being modified.
If a simple change of axis order is required, then the astPermAxes function may provide a more straightforward method of making the required changes to the FrameSet.
Any variant Mappings associated with the remapped Frame (except for the current
variant) will be lost as a consequence of calling this method (see attribute