Keywords - Function groups - @ A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Library: spatial
See also: SPPPinit SPPPinitrandom SPPPsetregion SPPPgetregion SPPPpsim SPPPstrauss SPPPssi SPPPkenvl SPPPkaver

Quantlet: SPPPkfn
Description: computes K-fn of a point pattern. Actually, it computes L = sqrt(K / pi). Note that SPPPinit or SPPPsetregion must have been called before.

Reference(s):

Link:
Usage: res = SPPPkfn(pp, fs, k)
Input:
pp list, (of type "PP") calculated by SPPPinit
fs scalar, full scale of the plot
k scalar, number of regularly spaced distances in (0, fs)
Output:
res list, consisting of components x, y, k, dmin and lm:
res.x n x 1 vector, distances
res.y n x 1 vector, L-fn values
res.k scalar, number of distances returned (which may be less than input k if fs is too large)
res.dmin scalar, minimum distance between a pair of points
res.lm scalar, maximum deviation from L(t) = t

Note:

Example:
; loads the spatial statistics library
library("spatial")
; reads a spatial data set
pines = read("pines.dat")
; initializes a point process
pinesobj = SPPPinit(pines, 0, 96, 0, 100, 10)
; calculates K-fn in interval(0, 5), split into 100 segments
ppkfn = SPPPkfn(pinesobj, 5, 100)
ppkfn.y
ppkfn.lm

Result:
Returns the L-fn for a point pattern, including some of
its major characteristics.

Contents of y
[  1,]        0
[  2,]        0
[  3,]        0
[  4,]        0
[  5,]  0.11477
...
[ 99,]   5.0106
[100,]   5.0488

Contents of lm
[1,]  0.30359



Author: J. Symanzik, 20000725 license MD*Tech
(C) MD*TECH Method and Data Technologies, 05.02.2006