curvs2 (3NCARG)

FUNCTION CURVS2(T,N,PARAM,X,Y,XP,YP,SIGMA,XO,YO)

This subroutine is a companion to CURV1S which must be called before calling this subroutine. CURV2S calculates an interpolated value for a smoothing spline under tension at a given point.

T

(real, input) A real value to be mapped onto the interpolating curve. Values of T between zero and one interpolate the original data; any values of T outside this range result in extrapolation.

N

(integer, input) The number of points which were specified to determine the curve in CURVS1.

PARAM

(real, input) The arc lengths as computed by CURVS1.

X

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

Y

(real, input) An array containing the Y-coordinate values of the specified points.

XP

(real, input) An array of second derivative values as calculated by CURVS1.

YP

(real, input) An array of second derivative values as calculated by CURVS1.

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.

XO

(real, output) The interpolated X value.

YO

(real, output) The interpolated Y value.

To use CURV2, load the NCAR Graphics library ngmath.

curvs1, 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.