runifdisc {spatstat.random}

Generate N Uniform Random Points in a Disc

Description

Generate a random point pattern containing n independent uniform random points in a circular disc.

Usage

 runifdisc(n, radius=1, centre=c(0,0), ..., nsim=1, drop=TRUE)

Arguments

n

Number of points.

radius

Radius of the circle.

centre

Coordinates of the centre of the circle.

...

Arguments passed to disc controlling the accuracy of approximation to the circle.

nsim

Number of simulated realisations to be generated.

drop

Logical. If nsim=1 and drop=TRUE (the default), the result will be a point pattern, rather than a list containing a point pattern.

Details

This function generates n independent random points, uniformly distributed in a circular disc.

It is faster (for a circular window) than the general code used in runifpoint.

To generate random points in an ellipse, first generate points in a circle using runifdisc, then transform to an ellipse using affine, as shown in the examples.

To generate random points in other windows, use runifpoint. To generate non-uniform random points, use rpoint.

Value

A point pattern (an object of class "ppp") if nsim=1, or a list of point patterns if nsim > 1.

Author(s)

Adrian Baddeley [e-mail] and Rolf Turner [e-mail].

See Also

disc, runifpoint, rpoint

Examples

 # 100 random points in the unit disc
 plot(runifdisc(100))
 # 42 random points in the ellipse with major axis 3 and minor axis 1
 X <- runifdisc(42)
 Y <- affine(X, mat=diag(c(3,1)))
 plot(Y)