F nearest neighbour distribution function
Calculates an estimate of the F nearest neighbour distribution function
Fhat(pts1,pts2,s)
pts1 |
A points data set |
pts2 |
A points data set |
s |
A vector of distances at which to evaluate Fhat |
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.
A vector of the same length as s, containing the value of Fhat at the
distances in s.
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: https://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.
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)
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