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Convex hull



K = convhull(x,y) returns indices into the x and y vectors of the points on the convex hull.

convhull uses Qhull.

K = convhull(x,y,options) specifies a cell array of strings options to be used in Qhull via convhulln. The default option is {'Qt'}.

If options is [], the default options are used. If options is {''}, no options will be used, not even the default. For more information on Qhull and its options, see

[K,a] = convhull(...) also returns the area of the convex hull.


Use plot to plot the output of convhull.


Example 1.

Example 2. The following example illustrates the options input for convhull. The following commands

return a warning.

To suppress this warning, use the option 'Pp'. The following command passes the option 'Pp', along with the default 'Qt', to convhull.


convhull is based on Qhull [2]. For information about Qhull, see For copyright information, see

See Also

convhulln, delaunay, plot, polyarea, voronoi


[1]  Barber, C. B., D.P. Dobkin, and H.T. Huhdanpaa, "The Quickhull Algorithm for Convex Hulls," ACM Transactions on Mathematical Software, Vol. 22, No. 4, Dec. 1996, p. 469-483. Available in PDF format at citations/journals/toms/1996-22-4/p469-barber/.

[2]  National Science and Technology Research Center for Computation and Visualization of Geometric Structures (The Geometry Center), University of Minnesota. 1993.

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