R: F nearest neighbour distribution function

Fhat {splancs} | R Documentation

## F nearest neighbour distribution function

### Description

Calculates an estimate of the F nearest neighbour distribution function

### Usage

    Fhat(pts1,pts2,s)

### Arguments

`pts1` | A points data set
`pts2` | A points data set
`s` | A vector of distances at which to evaluate Fhat

### Details

The function `Fhat(pts1,pts2,s)` is defined as the proportion of members of a point set `pts2` for which the distance to the nearest member of another points set `pts1` is less than or equal to `s`.

### Value

A vector of the same length as `s`, containing the value of Fhat at the distances in `s`.

### References

Rowlingson, B. and Diggle, P. 1993 Splancs: spatial point pattern analysis code in S-Plus. Computers and Geosciences, 19, 627-655; the original sources can be accessed at: http://www.maths.lancs.ac.uk/~rowlings/Splancs/. See also Bivand, R. and Gebhardt, A. 2000 Implementing functions for spatial statistical analysis using the R language. Journal of Geographical Systems, 2, 307-317.

### See Also

`nndistF`,`Fzero`

### Examples

    data(uganda)
    plot(seq(20, 500, 20), Fhat(as.points(uganda),
    as.points(csr(uganda$poly, length(uganda$x))), seq(20, 500, 20)),
    type="l", xlab="distance", ylab="Estimated F")
    plot(Ghat(as.points(uganda), seq(20, 500, 20)), Fhat(as.points(uganda),
    as.points(csr(uganda$poly, length(uganda$x))), seq(20, 500, 20)),
    type="l", xlab="Estimated G", ylab="Estimated F")
    lines(c(0,1),c(0,1),lty=2)

[Package splancs version 2.01-40 Index]