I/o-efficient efficient algorithms for computing contours on a terrain
Pankaj K. Agarwal, Lars Arge, Thomas Mølhave, Bardia Sadri · 2008
A terrain M is the graph of a bivariate function. We assume that M is represented as a triangulated surface with N vertices. A contour (or isoline) of M is a connected component of a level set of M. Generically, each contour is a closed polygonal curve; at "critical" levels these curves may touch each other or collapse to a point. We present I/O efficient algorithms for the following two problems related to computing contours of M: