can be reduced to a situation in which each remaining label has only two potential positions in which it can be placed, then it may be solved efficiently by using an instance of 2-satisfiability to find a placement avoiding any conflicting pairs of placements; several exact and approximate label placement algorithms for more complex types of problems are based on this principle. Other algorithms Automatic label placement algorithms can use any of the algorithms for finding the maximum disjoint set from the set of potential labels. Other algorithms can also be used, like various graph solutions, integer programming etc. Notes References Freeman, H., Map data processing and the annotation problem, Proc. 3rd Scandinavian Conf. on Image Analysis, Chartwell-Bratt Ltd. Copenhagen, 1983. Ahn, J. and Freeman, H., “A program for automatic name placement,” Proc. AUTO-CARTO 6, Ottawa, 1983. 444–455. Freeman, H., “Computer Name Placement,” ch. 29, in Geographical Information Systems, 1, D.J. Maguire, M.F. Goodchild, and D.W. Rhind, John Wiley, New York, 1991, 449–460. Podolskaya N. N. Automatic Label De-Confliction Algorithms for Interactive Graphics Applications. Information technologies (ISSN 1684-6400), 9, 2007, p. 45–50. In Russian: Подольская Н.Н. Алгоритмы автоматического отброса формуляров для интерак тивных графических приложений. Информационные технологии, 9, 2007, с. 45–50. Kameda, T. and K. Imai. 2003. Map label placement for points and curves. IEICE Transactions of Fundamentals of Electronics Communications and Computer Sciences. E86A(4):835–840. Ribeiro Glaydston and Luiz Lorena. 2006. Heuristics for cartographic label placement problems. Computers & Geosciences. 32:739–748. Wagner, F., A. Wolff, V. Kapoor, and T. Strijk. 2001. Three Rules Suffice for Good Label Placement. Algorithmica. 30:334–349. External links Alexander Wolff's Map Labeling Site The Map-Labeling Bibliography Label placement An Empirical Study of Algorithms for Point-Feature Label Placement Optimization algorithms and methods Geographic information systems