Curve fitting and editing via interactive graphics

Abstract

The system described here allows a user to enter a curve into an IBM 360/40 computer via a RAND tablet [1], and interactively to specify various ways of fitting, editing and displaying the curve on an IBM 2250 scope (see Fig. 1). It was developed primarily as a tool to extend the analysis of multivariate function representation (described by Boehm [2]) from tabular methods to polynomial methods. We decided to use an interactive graphics approach for three main reasons: 1. Experience has shown that much time is spent visually editing curves for input errors; this used to be done on an SC-4020 with one-day turn-around. 2. We wanted to experiment rapidly with choice of form, as multivariate functions are hard to classify in terms of representability. 3. The facility was available, along with a basic software support package.