R: Simulate Stratified Random Point Pattern

rstrat {spatstat.core} | R Documentation

## Simulate Stratified Random Point Pattern

### Description

Generates a “stratified random” pattern of points in a window, by dividing the window into rectangular tiles and placing `k` random points independently in each tile.

### Usage

     rstrat(win=square(1), nx, ny=nx, k = 1, nsim=1, drop=TRUE)

### Arguments

`win` | A window. An object of class `owin`, or data in any format acceptable to `as.owin()`.
`nx` | Number of tiles in each column.
`ny` | Number of tiles in each row.
`k` | Number of random points to generate in each tile.
`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 a random pattern of points in a “stratified random” sampling design. It can be useful for generating random spatial sampling points.

The bounding rectangle of `win` is divided into a regular nx * ny grid of rectangular tiles. In each tile, `k` random points are generated independently with a uniform distribution in that tile.

Some of these grid points may lie outside the window `win`: if they do, they are deleted.

The result is a point pattern inside the window `win`.

This function is useful in creating dummy points for quadrature schemes (see `quadscheme`) as well as in simulating random point patterns.

### 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

`rsyst`, `runifpoint`, `quadscheme`

### Examples

      X <- rstrat(nx=10)
      plot(X)

      # polygonal boundary
      X <- rstrat(letterR, 5, 10, k=3)
      plot(X)

[Package spatstat.core version 2.0-0 Index]