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.

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

nx

Number of tiles in each row.

ny

Number of tiles in each column.

k

Number of random points to generate in each tile.

A list with two components `x`

and `y`

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

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.

# NOT RUN { 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]) # }