R: Standard errors for the difference between two K-functions

secal {splancs} | R Documentation

## Standard errors for the difference between two K-functions

### Description

Calculate standard errors for the difference between two K-functions under random labelling of the corresponding two sets of points.

### Usage

    secal(pts1,pts2,poly,s)

### Arguments

`pts1,pts2` | Two point data sets
`poly` | Polygon enclosing the points in `pts1` and `pts2`
`s` | A vector of distances at which to calculate the standard error.

### Details

To compare two point patterns, one can calculate the difference between their K-functions. The function `secal` gives the pointwise standard errors for the estimated differences, under the random labelling hypothesis.

### Value

A vector like `s` containing the value of the standard error at each of the distances in `s`

### References

Diggle P.J. and Chetwynd A.G. (1991) Second-order analysis of spatial clustering Biometrics 47 1155–63; 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

`khat`

[Package splancs version 2.01-40 Index]