spatstat (version 1.16-1)

# runifpoint: Generate N Uniform Random Points

## Description

Generate a random point pattern containing \$n\$ independent uniform random points.

## Usage

`runifpoint(n, win=owin(c(0,1),c(0,1)), giveup=1000)`

## Arguments

n
Number of points.
win
Window in which to simulate the pattern. An object of class `"owin"` or something acceptable to `as.owin`.
giveup
Number of attempts in the rejection method after which the algorithm should stop trying to generate new points.

## Value

• The simulated point pattern (an object of class `"ppp"`).

## Details

This function generates `n` independent random points, uniformly distributed in the window `win`. (For nonuniform distributions, see `rpoint`.)

The algorithm depends on the type of window, as follows:

• If`win`is a rectangle then\$n\$independent random points, uniformly distributed in the rectangle, are generated by assigning uniform random values to their cartesian coordinates.
• If`win`is a binary image mask, then a random sequence of pixels is selected (using`sample`) with equal probabilities. Then for each pixel in the sequence we generate a uniformly distributed random point in that pixel.
• If`win`is a polygonal window, the algorithm uses the rejection method. It finds a rectangle enclosing the window, generates points in this rectangle, and tests whether they fall in the desired window. It gives up when`giveup * n`tests have been performed without yielding`n`successes.
The algorithm for binary image masks is faster than the rejection method but involves discretisation.

## See Also

`ppp.object`, `owin.object`, `rpoispp`, `rpoint`

## Examples

Run this code
``````# 100 random points in the unit square
pp <- runifpoint(100)
# irregular window
data(letterR)
# polygonal
pp <- runifpoint(100, letterR)
# binary image mask
pp <- runifpoint(100, as.mask(letterR))``````

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