Variogram.default {nlme} | R Documentation |
This method function calculates the semi-variogram for an arbitrary
vector object
, according to the distances in distance
.
For each pair of elements x,y in object
, the
corresponding semi-variogram is (x-y)^2/2. The semi-variogram is
useful for identifying and modeling spatial correlation structures in
observations with constant expectation and constant variance.
## Default S3 method: Variogram(object, distance, ...)
object |
a numeric vector with the values to be used for calculating the semi-variogram, usually a residual vector from a fitted model. |
distance |
a numeric vector with the pairwise distances
corresponding to the elements of object . The order of the
elements in distance must correspond to the pairs
(1,2), (1,3), ..., (n-1,n) , with n representing the
length of object , and must have length n(n-1)/2 . |
... |
some methods for this generic require additional arguments. None are used in this method. |
a data frame with columns variog
and dist
representing,
respectively, the semi-variogram values and the corresponding
distances. The returned value inherits from class Variogram
.
Jose Pinheiro Jose.Pinheiro@pharma.novartis.com and Douglas Bates bates@stat.wisc.edu
Cressie, N.A.C. (1993), "Statistics for Spatial Data", J. Wiley & Sons.
Variogram.gls
, Variogram.lme
,
plot.Variogram
## Not run: fm1 <- lm(follicles ~ sin(2 * pi * Time) + cos(2 * pi * Time), Ovary, subset = Mare == 1) Variogram(resid(fm1), dist(1:29))[1:10,] ## End(Not run)