This task can be used to extract data from a file for a
particular time slice. The world coordinates will be valid on
this slice so the data can be used for display or image overlay
(e.g. when using the KAPPA OUTLINE command to determine where
this slice lies in relation to the reconstructed map).
KAPPA NDFCOPY will not add the specific astrometry information when
used to extract a slice and so cannot be used when WCS is required.