This routine joins a series of points specified in the physical
coordinate system of a Plot by drawing a sequence of geodesic
curves. It is equivalent to making repeated calls to the
AST_CURVE routine (q.v.), except that AST_POLYCURVE will
generally be more efficient when drawing many geodesic curves
end-to-end. A typical application of this might be in drawing
contour lines.
As with AST_CURVE, full account is taken of the Mapping between
physical and graphical coordinate systems. This includes any
discontinuities and clipping established using AST_CLIP.