plot.ahull {alphahull} R Documentation

Plot the alpha-convex hull

Description

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.

Usage

## 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, ...)

Arguments

 x Object of class "ahull". add Logical, if TRUE add to a current plot. do.shape Logical, indicates if the α-shape should also be plotted. wlines "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)? wpoints Logical, indicates if sample points should be plotted. number Logical, defaulting to FALSE; if TRUE then the points plotted will be labelled with their index numbers. col 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.) xlim The limits on the x-axis. ylim The limits on the y-axis. lwd 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).

Examples

## 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)
plot(ahull.obj)

## End(Not run)

[Package alphahull version 2.2 Index]