# convex_hull: Draw different types of convex hulls around a set of points In markheckmann/convexhull: Drawing convex hulls

## Description

Draw different types of convex hulls around a set of points

## Usage

 ```1 2``` ```convex_hull(x, y = NULL, alpha = 0, peel = FALSE, smooth = 0, shape = 1, draw = TRUE, ...) ```

## Arguments

 `x,y` The x and y coordinates of a set of points. Alternatively, a single argument x can be provided. `alpha` Proportion of points most distant from centroid to be removed before creating the (peeled) convex hull. `peel` Remove hull points? (useful to remove outliers, default `FALSE`) `smooth` Integer (`1` to `3`) indicating the method for creating splines around the hull. `0` (default) is no smooting. `shape` Shape parameter used for `smooth=1` (see `xspline` for details). `draw` Draw the hull polygon (default `TRUE`). `...` additional parameters passed to `polygon` to draw the hull.

## Value

A list as given by `xy.coords` containing the hull points is returned invisibly.

## Examples

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24``` ```set.seed(2) x <- rnorm(100) y <- rnorm(100) op <- par(mfrow=c(2,3), mar=c(3,2,3,1)) plot(x,y, main="convex hull") convex_hull(x,y) plot(x,y, main="colored hull") convex_hull(x,y, col="#FF000050", density=10, angle=45, border="red") plot(x,y, main="20% of most distant\npoints removed") convex_hull(x,y, alpha=.2, col="#FF000050", density=10, angle=45, border="red") plot(x,y, main="initial hull points\nremoved (peeled off)") convex_hull(x,y, peel=TRUE, col="#00FF0050", border="red") plot(x,y, main="smoothed hull\n(spline interpolated)") convex_hull(x,y, smooth=2, col="#FF000050", border="red") plot(x,y, main="another smooting\nmethod") convex_hull(x,y, peel=TRUE, smooth=1, shape=1, col="#00FF0050", border="red") par(op) ```

markheckmann/convexhull documentation built on May 21, 2019, 12:06 p.m.