Perform projection operations for Orthographic (SIN) projection
CALL WCI1_XPSIN( OP, UNPROJ, NPAR, PARAM, PROJ, STATUS )
Performs conversions for the SIN projection. This is a perspective zenithal projection where the plane of projection is tangent to the sphere at the special point, and the source of the projection is at infinity.UNPROJ are the native spherical coordinates, PROJ are the projected linearised x,y coordinates.