Real time plotting of approximate contour maps
Stephen A. Ward · Communications of the ACM · 1978
Real Time Plotting of Approximate Contour Mapswell as the plot resolution at ead~ character position.In general, the approach described requires 6n 2 special characters (plus overstriking) for an order n contour map.Thus order one contour maps may be output via a terminal or other device augmented by six additional characters; a 96-character programmable-font device may be used to produce order four countours. The Algorithm