AbstractGet full access to this articleView all access options for this article.Get accessReferences1.Lectric Lites Co. 2054 W. Vickery Blvd, Fort Worth, Texas, USA.2.Automatic Systems Laboratories, Saxon Street, Linfold Wood, Milton Keynes, Bucks, UK.3.Collected algorithms form ACM, Algorithm 510 (1976), Piecewise linear approximations to tabulated data, D G Wilson, Oak Ridge National Laboratory, Tennessee, USA.