# stratrand

From spatstat v1.5-9
by Adrian Baddeley

##### Stratified random point pattern

Generates a ``stratified random'' pattern of points in a window,
by dividing the window into rectangular tiles and placing
`k`

random points in each tile.

- Keywords
- spatial

##### Usage

`stratrand(window, nx, ny, k = 1)`

##### Arguments

##### Details

The bounding rectangle of `window`

is divided into
a regular $nx \times ny$ grid of rectangular tiles.
In each tile, `k`

random points are generated independently
with a uniform distribution in that tile.

Note that some of these grid points may lie outside the window,
if `window`

is not of type `"rectangle"`

. The function
`inside.owin`

can be used to select those grid points
which do lie inside the window. See the examples.

This function is useful in creating dummy points for quadrature
schemes (see `quadscheme`

) as well as in simulating
random point patterns.

##### Value

- A list with two components
`x`

and`y`

, which are numeric vectors giving the coordinates of the random points.

##### See Also

##### Examples

```
w <- unit.square()
xy <- stratrand(w, 10, 10)
plot(w)
points(xy)
# polygonal boundary
bdry <- list(x=c(0.1,0.3,0.7,0.4,0.2),
y=c(0.1,0.1,0.5,0.7,0.3))
w <- owin(c(0,1), c(0,1), poly=bdry)
xy <- stratrand(w, 10, 10, 3)
plot(w)
points(xy)
# determine which grid points are inside polygon
ok <- inside.owin(xy$x, xy$y, w)
plot(w)
points(xy$x[ok], xy$y[ok])
```

*Documentation reproduced from package spatstat, version 1.5-9, License: GPL version 2 or newer*

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