convhull
Convex hull
Note:
Qhull-specific options are no longer supported. Remove the |
Syntax
K = convhull(X,Y)
K = convhull(X,Y,Z)
K = convhull(X)
K = convhull(...,'simplify', logicalvar)
[K,V] = convhull(...)
Definitions
convhull returns the convex hull of a set
of points in 2-D or 3-D space.
Description
K = convhull(X,Y) returns
the 2-D convex hull of the points (X,Y),
where X and Y are column vectors.
The convex hull K is expressed in terms of a vector
of point indices arranged in a counterclockwise cycle around the hull.
K = convhull(X,Y,Z) returns
the 3-D convex hull of the points (X,Y,Z),
where X, Y, and Z are
column vectors. K is a triangulation representing
the boundary of the convex hull. K is of size mtri-by-3,
where mtri is the number of triangular facets.
That is, each row of K is a triangle defined in
terms of the point indices.
K = convhull(X) returns
the 2-D or 3-D convex hull of the points X. This
variant supports the definition of points in matrix format. X is
of size mpts-by-ndim, where mpts is
the number of points and ndim is the dimension
of the space where the points reside, 2 ≦ ndim ≦
3. The output facets are equivalent to those generated by the 2-input
or 3-input calling syntax.
K = convhull(...,'simplify', logicalvar) provides
the option of removing vertices that do not contribute to the area/volume
of the convex hull, the default is false. Setting 'simplify' to
true returns the topology in a more concise form.
[K,V] = convhull(...) returns
the convex hull K and the corresponding area/volume V bounded
by K.
Visualization
Use plot to plot the
output of convhull in 2-D. Use trisurf or trimesh to
plot the output of convhull in 3-D.
Examples
Plot 2-D Convex Hull
xx = -1:.05:1; yy = abs(sqrt(xx)); [x,y] = pol2cart(xx,yy); k = convhull(x,y); plot(x(k),y(k),'r-',x,y,'b*')
See Also
convexHull | convhulln | delaunay | polyarea | voronoi | voronoiDiagram