Minimax location of two facilities with minimum separation: Interactive graphical solutions

The authors consider the problem of locating two facilities so as to minimize the maximum of combined Euclidean distances to unweighted existing points when the facilities must be separated by at least a specified distance. Interpreting the problem as the minimum covering ellipse probelm, they employ an interactive graphical method which easily produces near-optimal solutions. The authors describe the method, implemented on a microcomputer, because it exemplifies the more general technique of interactive optimization.