NAME

       KURVP2 - does interpolation for closed parametric curves

SYNOPSIS

       CALL KURVP2 (T, XS, YS, N, X, Y, XP, YP, S, SIGMA)

       The  interpolated curve is parameterized by mapping points in the interval [0.,1.] onto an
       interpolated closed curve. The resulting curve has a  parametric  representation  both  of
       whose  components are splines under tension and functions of the polygonal arc length. The
       value 0.  is mapped onto (X[1],Y[1]) and the value 1. is  also  mapped  onto  (X[1],Y[1]),
       since the interpolated curve is closed. KURVP1 must be called before calling KURVP2.

DESCRIPTION

       T           (real,input)  A  value  to  be  mapped  to  a point on the curve. The interval
                   [0.,1.] is mapped onto the curve such that 0. is mapped to (X(1),Y(1)) and  1.
                   is mapped to (X(1),Y(1)), since the interpolated curve is closed. Any interval
                   [TT,TT+1.] maps onto the entire curve.

       XS          (real, oputput) Contains the X coordinate of the  interpolated  point  that  T
                   maps to.

       YS          (real,  oputput)  Contains  the  Y coordinate of the interpolated point that T
                   maps to.

       N           (integer, input) The number of input data points. (N > 1)

       X           (real, input) An array containing the X values of the input points.

       Y           (real, input) An array containing the Y values of the input  points.  Adjacent
                   pairs of points must be distinct.

       XP          (real, input) An array of length N as computed by KURVP1.

       YP          (real, input) An array of length N as computed by KURVP1.

       S           (real, input) An array of length N containing the polygonal arc lengths of the
                   curve.

       SIGMA       (real, input) Tension factor. Values near zero result in a cubic spline; large
                   values (e.g. 50) result in nearly a polygonal line. A typical value is 1.

ACCESS

       To use KURVP2, load the NCAR Graphics library ngmath.

SEE ALSO

       kurvp1, fitgrid_params.

       Complete documentation for Fitgrid is available at URL
       http://ngwww.ucar.edu/ngdoc/ng/ngmath/fitgrid/fithome.html

COPYRIGHT

       Copyright (C) 2000
       University Corporation for Atmospheric Research

       The use of this Software is governed by a License Agreement.