Perform projection operations for zenithal perspective (AZP) projection
CALL WCI1_XPAZP( OP, UNPROJ, NPAR, PARAM, PROJ, STATUS )
Performs conversions for the AZP projection. This the general perspective zenithal projection where the plane of projection is tangent to the sphere at the special point, and the source of the projection is lies on a line passing through the special point and the centre of the sphere.UNPROJ are the native spherical coordinates, PROJ are the projected linearised x,y coordinates.