% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/hullplot.R
\name{hullplot}
\alias{hullplot}
\title{Plot Convex Hulls of Clusters}
\usage{
hullplot(
  x,
  cl,
  col = NULL,
  cex = 0.5,
  hull_lwd = 1,
  hull_lty = 1,
  solid = TRUE,
  alpha = 0.2,
  main = "Convex Cluster Hulls",
  ...
)
}
\arguments{
\item{x}{a data matrix. If more than 2 columns are provided, then the data
is plotted using the first two principal components.}

\item{cl}{a clustering. Either a numeric cluster assignment vector or a
clustering object (a list with an element named \code{cluster}).}

\item{col}{colors used for clusters. Defaults to the standard palette.  The
first color (default is black) is used for noise/unassigned points (cluster
id 0).}

\item{cex}{expansion factor for symbols.}

\item{hull_lwd, hull_lty}{line width and line type used for the convex hull.}

\item{solid, alpha}{draw filled polygons instead of just lines for the convex
hulls? alpha controls the level of alpha shading.}

\item{main}{main title.}

\item{...}{additional arguments passed on to plot.}
}
\description{
This function produces a two-dimensional scatter plot with added convex
hulls for clusters.
}
\examples{
set.seed(2)
n <- 400

x <- cbind(
  x = runif(4, 0, 1) + rnorm(n, sd = 0.1),
  y = runif(4, 0, 1) + rnorm(n, sd = 0.1)
  )
cl <- rep(1:4, time = 100)

### original data with true clustering
hullplot(x, cl, main = "True clusters")
### use differnt symbols
hullplot(x, cl, main = "True clusters", pch = cl)
### just the hulls
hullplot(x, cl, main = "True clusters", pch = NA)
### a version suitable for b/w printing)
hullplot(x, cl, main = "True clusters", solid = FALSE, col = "black", pch = cl)


### run some clustering algorithms and plot the resutls
db <- dbscan(x, eps = .07, minPts = 10)
hullplot(x, db, main = "DBSCAN")

op <- optics(x, eps = 10, minPts = 10)
opDBSCAN <- extractDBSCAN(op, eps_cl = .07)
hullplot(x, opDBSCAN, main = "OPTICS")

opXi <- extractXi(op, xi = 0.05)
hullplot(x, opXi, main = "OPTICSXi")

# Extract minimal 'flat' clusters only
opXi <- extractXi(op, xi = 0.05, minimum = TRUE)
hullplot(x, opXi, main = "OPTICSXi")

km <- kmeans(x, centers = 4)
hullplot(x, km, main = "k-means")

hc <- cutree(hclust(dist(x)), k = 4)
hullplot(x, hc, main = "Hierarchical Clustering")

}
\author{
Michael Hahsler
}
\keyword{clustering}
\keyword{plot}
