convexhull - Maple Help

geometry

 convexhull
 find the convex hull enclosing the given points

 Calling Sequence convexhull(ps)

Parameters

 ps - list or set of points

Description

 • The convex hull of a set ps of points is the smallest convex polygon P for which each point in ps is either on the boundary of P or in its interior.
 • The result is returned as a list of points (vertices) of the convex polygon P in counter-clockwise order.
 • The routine uses an $n\mathrm{log}\left(n\right)$ algorithm computing tangents of pairs of points.
 • For an equivalent command with a few more options, see simplex[convexhull].  Input and output are simple points rather than geometric points, and the output can be the area enclosed in the polygon, the points defining the vertices, or a plot of the polygon.
 • The command with(geometry,convexhull) allows the use of the abbreviated form of this command.

Examples

 > $\mathrm{with}\left(\mathrm{geometry}\right):$
 > $\mathrm{point}\left(A,\left[0,0\right]\right),\mathrm{point}\left(B,\left[1,1\right]\right),\mathrm{point}\left(C,\left[2,0\right]\right),\mathrm{point}\left(F,\left[1,0\right]\right),\mathrm{point}\left(\mathrm{E1},\left[1,\frac{1}{2}\right]\right):$
 > $\mathrm{hullname}≔\mathrm{convexhull}\left(\left\{A,B,C,\mathrm{E1},F\right\}\right)$
 ${\mathrm{hullname}}{≔}\left[{A}{,}{C}{,}{B}\right]$ (1)
 > $\mathrm{triangle}\left(T,\mathrm{hullname}\right):$
 > $\mathrm{draw}\left(\left\{A,B,C,\mathrm{E1},F,T\right\},\mathrm{printtext}=\mathrm{true},\mathrm{axes}=\mathrm{NONE}\right)$