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.html

See Also

point, pairs

Examples

maas.v<-est.variogram(maas.pts,maas.pairs,'zinc') 


[Package Contents]