Variogram Estimator
Usage
est.variogram(point.obj, pairs.obj, v1, v2=v1)
Arguments
point.obj
|
a point object generated by point()
|
pairs.obj
|
a pairs object generated by pairs()
|
v1
|
a variable to calculate semivariogram for
|
v2
|
an optional variable name, if entered cross variograms will be created between v1 and v2
|
Description
Calculate empirical variogram estimates.
An object of class variogram
contains empirical variogram estimates generated from a point object and a pairs object. A
variogram object is stored as a data frame containing six columns: lags
, bins
, classic
, robust
, med
, and n
. The length of each
vector is equal to the number of lags in the pairs object used to create the variogram object, say l. The lags
vector contains the
lag numbers for each lag, beginning with one (1) and going to the number of lags (l). The bins
vector contains the spatial midpoint
of each lag. The classic
, robust
, and med
vectors contain the classical, robust, and median variogram estimates for each lag,
respectively (see Cressie, 1993, p. 75). The n
vector contains the number of pairs of points in each lag.
Value
A variogram object:
lags
|
vector of lag identifiers
|
bins
|
vector of midpoints of each lag
|
classic
|
vector of classic variogram estimates for each lag
|
robust
|
vector of robust variogram estimates for each lag
|
med
|
vector of median variogram estimates for each lag
|
n
|
vector of the number of pairs in each lag
|
References
http://www.gis.iastate.edu/SGeoStat/homepage.htmlSee Also
point
, pairs
Examples
maas.v<-est.variogram(maas.pts,maas.pairs,'zinc')