Library: | spatial |
See also: | SPKRsurfls SPKRsurfgls SPKRexpcov SPKRgaucov SPKRtrmat SPKRprmat SPKRsemat SPKRcorrelogram SPKRvariogram SPKRmultcontours |
Quantlet: | SPKRsphercov | |
Description: | spatial covariance function for use with SPKRsurfgls |
Usage: | res = SPKRsphercov(r, d, alpha, se {, D}) | |
Input: | ||
r | n x 1 vector, distances used to evaluate the covariance | |
d | scalar, range parameter | |
alpha | scalar, proportion of nugget effect | |
se | scalar, standard deviation at distance zero | |
D | optional scalar, dimension of spheres; default D = 2 | |
Output: | ||
res | n x 1 vector, covariance values |
; loads the spatial statistics library library("spatial") ; calculates spatial covariance function SPKRsphercov ; with d = 0.7, alpha = 0, se = 1, and D = 2 on a grid ; from 0 through 7 ddat = grid(0, 0.1, 71) linedat = ddat ~ SPKRsphercov(ddat, 0.7, 0, 1, 2) ; creates a display and draws the covariance disp = createdisplay(1, 1) show(disp, 1, 1, linedat)
A plot of the vector of covariance values. Typically, this quantlet is used together with SPKRsurfgls or SPKRcorrelogram.