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Planar Straight Line Embedding


A planar straight line embedding of a planar graph is a planar graph embedding whose edges are straight line segments meeting only at common endpoints. The common-endpoint condition distinguishes a planar straight line embedding from a general straight line drawing, whose edges may have other intersections. The Fáry theorem establishes that every finite graph that is simple and planar has a planar straight line embedding (Bryant 1989; Skiena 1990, pp. 100 and 251; Scheinerman and Wilf 1994), and these embeddings, which have rectilinear crossing number 0, are sometimes known as Fáry embeddings.

Every prescribed planar graph embedding of a finite graph that is simple has an equivalent planar straight line embedding. This redrawing preserves the embedding, including its rotation system and chosen outer graph face, while allowing graph vertex coordinates to change (Erickson 2023).

A planar straight line embedding of a planar graph can be constructed in the Wolfram Language using the "PlanarEmbedding" option to GraphLayout or in the Wolfram Language using PlanarGraph[g].

de Fraysseix et al. (1988) give an algorithm for constructing a planar straight line embedding for a simple planar graph of vertex count n>=3 by placing the vertices on a (2n-4)×(n-2) grid (Skiena 1990, p. 251).


See also

Fáry Theorem, Graph Embedding, Planar Graph, Planar Graph Embedding, Rectilinear Crossing Number, Straight Line Drawing

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References

Bondy, J. A. and Murty, U. S. R. Graph Theory with Applications. New York: North Holland, p. 139, 1976.Brandenburg, F. J. "Straight-Line Drawings of 1-Planar Graphs." 3 Sep 2021. https://arxiv.org/abs/2109.01692.Bryant, V. W. "Straight Line Representation of Planar Graphs." Elem. Math. 44, 64-66, 1989.de Fraysseix, H.; Pach, J; and Pollack, R. "Small Sets Supporting Fáry Embeddings of Planar Graphs." Proc. of the 20th Symposium on the Theory of Computing. ACM, pp. 426-433, 1988.Erickson, J. "Straight-Line Planar Maps." One-Dimensional Computational Topology course notes. 2023. https://jeffe.cs.illinois.edu/teaching/comptop/2023/notes/11-straight-line-planar.html.Fáry, I. "On Straight Line Representations of Planar Graphs." Acta Sci. Math. (Szeged) 11, 229-233, 1948.Gross, J. T. and Yellen, J. Graph Theory and Its Applications. Boca Raton, FL: CRC Press, pp. 629 and 638, 1999.Scheinerman, E. and Wilf, H. S. "The Rectilinear Crossing Number of a Complete Graph and Sylvester's 'Four Point' Problem of Geometric Probability." Amer. Math. Monthly 101, 939-943, 1994.Skiena, S. Implementing Discrete Mathematics: Combinatorics and Graph Theory with Mathematica. Reading, MA: Addison-Wesley, 1990.West, D. B. Introduction to Graph Theory, 2nd ed. Englewood Cliffs, NJ: Prentice-Hall, p. 247, 2000.

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Planar Straight Line Embedding

Cite this as:

Weisstein, Eric W. "Planar Straight Line Embedding." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/PlanarStraightLineEmbedding.html

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