Library: | spatial |
See also: | SPKRsurfls SPKRsurfgls SPKRexpcov SPKRgaucov SPKRsphercov SPKRtrmat SPKRprmat SPKRsemat SPKRcorrelogram SPKRmultcontours |
Quantlet: | SPKRvariogram | |
Description: | Computes spatial (semi-)variograms of spatial data or residuals. Initially, it divides the range of the data into nint bins, and computes the average squared difference for pairs with separation in each bin. It returns results only for bins with 6 or more pairs. |
Usage: | varres = SPKRcorrelogram (krig, nint) | |
Input: | ||
krig | list - (of type "trls" or "trgls") calculated by SPKRsurfls or SPKRsurfgls | |
nint | scalar - number of bins to be used | |
Output: | ||
res | list - consisting of components xpres, ypres, cntres -- | |
xpres | n x 1 - vector of the x coordinates of the variogram | |
ypres | n x 1 - vector of the y coordinates of the variogram | |
cntres | n x 1 - vector of the number of pairs averaged per bin |
; load the spatial statistics library library ("spatial") ; read a spatial data set topo = read("topo.dat") ; calculate a polynomial regression surface of order 2 myres = SPKRsurfls (2, topo) ; calculate the correlogram, using 25 bins varres = SPKRvariogram (myres, 25)
A list consisting of x and y coordinates of the variogram and the number of pairs averaged per bin.
Library: | spatial |
See also: | SPKRsurfls SPKRsurfgls SPKRexpcov SPKRgaucov SPKRsphercov SPKRtrmat SPKRprmat SPKRsemat SPKRcorrelogram SPKRmultcontours |