R: Covariance matrix for the difference between two K-functions

khvc {splancs} | R Documentation

## Covariance matrix for the difference between two K-functions

### Description

Calculate the covariance matrix for the difference between two K-functions. Also return the contribution to the variance for each of the two point patterns,

### Usage

    khvc(pts1, pts2, poly, s)

### Arguments

`pts1` | An object containing the case locations.
`pts2` | An object containing the control locations.
`poly` | A polygon enclosing the locations in `pts1` and `pts2`
`s` | A vector of distances at which the calculation is to be made.

### Value

A list with four components:

`varmat` | The upper triangle of the covariance matrix.
`k11` | The variance of Khat for the cases
`k22` | The variance of Khat for the controls
`k12` | The covariance of Khat for the cases and Khat for controls.

### Note

Note that the diagonal of the covariance matrix is `$k11 - 2 * $k12 + $k22`

### 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

`khat`, `khvmat`, `secal`

[Package splancs version 2.01-40 Index]