To permit the calculation of the Stokes parameters, polarimetry recipes
resamples each frame using non-integer Cartesian offsets, or merely
finds the offsets between frames to the nearest pixel and shifts the
origin. The mosaic extends to include all pixels in contributing
the frames, however, in practice there should be at most one pixel
variation in dimensions.
[_RESAMPLE_MOSAICS_]
ORAC-DR -- imaging data reduction