Contour Smoothing by an Eclectic Procedure
Albert H. J. Christensen · Photogrammetric Engineering & Remote Sensing · 2001
A procedure that simply and effectively smoothes the contour lines derived from triangular irregular networks [TIN) is presented here. This procedure is shown to use both the TIN and its linearly interpolated contours (raw contours), which puts this process somewhere between the two smoothing approaches currently in use. Hence, the qualification of eclectic. The two approaches currently in use, smoothing of contours one at the time and independently of the others in the contour set, and contouring of smooth patches, are discussed with reference to objections that have been raised because of their shortcomings. The eclectic procedure presented in this paper is described as a simple splicing of arcs of quadratic parabolas, which gives an elegant look to the finished product and ensures that all source data elements are scrupulously honored. Additionally; the procedure is said to minimize the departures of the smoothed contours from the linear model embodied in the TIN. A simple modification to the basic procedure illustrates the manner in which the smoothing effect can be varied at will.