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

```
rsyst(win=square(1), nx=NULL, ny=nx, …, dx=NULL, dy=dx,
nsim=1, drop=TRUE)
```

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.

A point pattern (an object of class `"ppp"`

)
if `nsim=1`

, or a list of point patterns if `nsim > 1`

.

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.

```
# NOT RUN {
X <- rsyst(nx=10)
plot(X)
# polygonal boundary
data(letterR)
X <- rsyst(letterR, 5, 10)
plot(X)
# }
```

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