spatstat.geom: rsyst – R documentation

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rsyst

Simulate systematic random point pattern

Description

Generates a “systematic random” pattern of points in a window, consisting of a grid of equally-spaced points with a random common displacement.

Usage

rsyst(win=square(1), nx=NULL, ny=nx, ..., dx=NULL, dy=dx,
       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 columns of grid points in the window. Incompatible with `dx`.
`ny`	Number of rows of grid points in the window. Incompatible with `dy`.
`...`	Ignored.
`dx`	Spacing of grid points in x direction. Incompatible with `nx`.
`dy`	Spacing of grid points in y direction. Incompatible with `ny`.
`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 “systematic random” pattern of points in the window win. The pattern consists of a rectangular grid of points with a random common displacement.

The grid spacing in the x direction is determined either by the number of columns nx or by the horizontal spacing dx. The grid spacing in the y direction is determined either by the number of rows ny or by the vertical spacing dy.

The grid is then given a random displacement (the common displacement of the grid points is a uniformly distributed random vector in the tile of dimensions dx, dy).

Some of the resulting 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

Examples

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

  # polygonal boundary
  X <- rsyst(letterR, 5, 10)
  plot(X)

spatstat.geom

Geometrical Functionality of the 'spatstat' Family

v2.1-0

GPL (>= 2)

Authors

Adrian Baddeley [aut, cre], Rolf Turner [aut], Ege Rubak [aut], Tilman Davies [ctb], Ute Hahn [ctb], Abdollah Jalilian [ctb], Sebastian Meyer [ctb], Suman Rakshit [ctb], Dominic Schuhmacher [ctb], Rasmus Waagepetersen [ctb]

Initial release

2021-04-15