vario.calc {RGeostats}  R Documentation 
Computes various types of experimental variograms for irregular samplings, for one or several variables contained in a DB structure. If present (defined in the input Db), a set of weight is taken into account in the calculations. The variograms can be calculated with regular or not distance lags.
vario.calc(db, dirvect=NA,lag=NA, toldis=0.5, tolang=NA, bench=0, cylrad=0,nlag=NA, breaks = NA, calcul="vg", by.sample=FALSE, opt.code=0, tolcode=0, verr.mode=0, means=NA, uc=c("1"),struct=melem.name(c(1,4,5,2,3)), model=NA, vario.add=NA)
db 
The 
dirvect 
The directions in which the variogram must be calculated.
For more information, refer to 
lag 
Array containing the distance lags for each calculation direction. If no corresponding lag is not defined, a default lag is calculated so that the maximum distance is equal to half of the field diagonal. For one distance, if the lag is not defined, it is set to the default lag. 
toldis 
Tolerance on the distance, expressed as a proportion of the lag. This parameter is only used in the case of regular lags. 
tolang 
Array containing the angular tolerance for each calculation direction. If no angular tolerance is not defined, a default tolerance is calculated as one half of the angle. For one direction, if the angular tolerance is not defined, it is set to the default tolerance. 
bench 
Array containing the bench separation tolerance for each calculation direction. When bench is defined and positive, a pair is discarded if the separation distance between the two points along the third axis is larger than 'bench'. 
cylrad 
Array containing the cylrad tolerance for each calculation direction. When specified and positive, a pair is discarded if the separation distance in the plane orthogonal to the calculation distance is larger than 'cylrad'. 
nlag 
Array containing the number of lags for each calculation direction. If not defined, the defaulted number of lags is set to 10. For one direction, if the number of lags is not defined, it is set to 10. 
breaks 
Vector giving the boundaries of irregular distance lags. For multidrectional computations, breaks is either: a vector (The breaks are then the same for all directions) a list of vectors of the breaks for each direction. If provided, nlag is adapted to the breaks. Intervals are open left and closed right (e.g ]0;15]). 
calcul 
Character string giving the type of structure to compute:

by.sample 
This parameter drives the way the calculations are performed. When FALSE, the usual calculation is performed: all points (up to a certain distance) are compared. When TRUE, a variogram is calculated for each sample; then the different variograms are averaged. Note that in the case of Transitive Covariogram, this flag is set to TRUE automatically (as we apply the Regression algorithm from N. BEZ in the case of irregular data set). 
opt.code 
Array containing the option concerning the use of the code for each direction. This option defines the strategy for the code usage when considering a pair of samples:

tolcode 
Array giving the maximum distance between the codes of the two samples for each direction. 
verr.mode 
Type of correction when accounting for the Variance of Measurement Error (if defined in the input Db):

means 
Array corresponding to the estimated means of the variable using for the Poisson variogram calculation 
uc 
The drift description. Use command 
struct 
List of basic structures to be used. This model is used to debias the variogram of residuals. This option is only active when the argument uc is provided and is different from the Universalit condition alone ("1"). 
model 
When this 
vario.add 
When defined, the current variogram computation is concatenated to the contents of the current variogram. 
An experimental varioclass
structure.