plot.ahull {alphahull}R Documentation

Plot the alpha-convex hull


This function returns a plot of the α-convex hull. If desired, it also adds the Delaunay triangulation, Voronoi diagram and α-shape of the sample.


## S3 method for class 'ahull'
plot(x, add = FALSE, do.shape = FALSE, 
	wlines = c("none", "both", "del", "vor"), wpoints = TRUE, 
	number = FALSE, col = NULL, xlim = NULL, 
	ylim = NULL, lwd = NULL, ...)



Object of class "ahull".


Logical, if TRUE add to a current plot.


Logical, indicates if the α-shape should also be plotted.


"Which lines?". I.e. should the Delaunay triangulation be plotted (wlines='del'), should the Voronoi diagram be plotted (wlines='vor'), should both be plotted (wlines='both'), or none (wlines='none', the default)?


Logical, indicates if sample points should be plotted.


Logical, defaulting to FALSE; if TRUE then the points plotted will be labelled with their index numbers.


The colour numbers for plotting the α-convex hull, α-shape, data points, Delaunay triangulation, Voronoi diagram, and the point numbers, in that order; defaults to c(1,1,1,1,1,1). If fewer than six numbers are given, they are recycled. (If more than six numbers are given, the redundant ones are ignored.)


The limits on the x-axis.


The limits on the y-axis.


The line widths for plotting the tesselations, the α-shape, and the α-convex hull, in that order; defaults to c(1,1,2).


Arguments to be passed to methods, such as graphical parameters (see par).

See Also

ahull, ashape.


## Not run: 
# Random sample in the unit square
x <- matrix(runif(100), nc = 2)
# Value of alpha
alpha <- 0.2
# alpha-convex hull
ahull.obj <- ahull(x, alpha = alpha)
# Plot including the alpha-convex hull in pink, alpha-shape in blue, 
# sample points in black, voronoi diagram in green 
# and Delaunay triangulation in red 
plot(ahull.obj, do.shape = TRUE, wlines = "both", col = c(6, 4, 1, 2, 3))

# Random sample  from a uniform distribution on a Koch snowflake 
# with initial side length 1 and 3 iterations
x <- rkoch(2000, side = 1, niter = 3)
# Value of alpha
alpha <- 0.05
# Alpha-convex hull
ahull.obj <- ahull(x, alpha = alpha)

## End(Not run)

[Package alphahull version 2.2 Index]