For a WCS returns pixel scales along each axis of the image pixel at the
CRPIXlocation once it is projected onto the “plane of intermediate world coordinates” as defined in Greisen & Calabretta 2002, A&A, 395, 1061.
This function is concerned only about the transformation “image plane”->”projection plane” and not about the transformation “celestial sphere”->”projection plane”->”image plane”. Therefore, this function ignores distortions arising due to non-linear nature of most projections.
A world coordinate system object.