Calculate standard errors for the difference between two K-functions under random labelling of the corresponding two sets of points.
secal(pts1,pts2,poly,s)Two point data sets
Polygon enclosing the points in pts1 and pts2
A vector of distances at which to calculate the standard error.
A vector like s containing the value of the standard error at each of the
distances in s
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.
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.