R: Generate N Uniform Random Points in a Disc

runifdisc {spatstat} | R Documentation

## 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 Adrian.Baddeley@curtin.edu.au

and Rolf Turner r.turner@auckland.ac.nz

### 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)

[Package spatstat version 1.54-0 Index]