KURV2 - does interpolation for parametric curves
CALL KURV2 (T, XS, YS, N, X, Y, XP, YP, S, SIGMA)
The interpolated curve is parameterized by mapping points in the
interval [0.,1.] onto the interpolated 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 mapped onto (X[N],Y[N]). KURV1 must be
called before calling KURV2.
- 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(N),Y(N)). Values outside of [0.,1.] result in
extrapolation.
- 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 KURV1.
- YP
- (real, input) An array of length N as computed by KURV1.
- 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.
To use KURV2, load the NCAR Graphics library ngmath.
kurv1, fitgrid_params.
Complete documentation for Fitgrid is available at URL
http://ngwww.ucar.edu/ngdoc/ng/ngmath/fitgrid/fithome.html
Copyright (C) 2000
University Corporation for Atmospheric Research
The use of this Software is governed by a License Agreement.